JP2002338294A - Glass and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide glass with which a photoelastic constant can be properly set and the low photoelasticity is made compatible with a low refractive index and manufacturing is easy, and a method for manufacturing the same. SOLUTION: The photoelastic constant is given as a function of a molar ratio and when the molar ratio of a mesh modification component and a mesh formation component is determined, the photoelastic constant is easily obtained, by which raw materials are properly regulated in such a manner that the molar ratio of the mesh modification component and the mesh formation component attains a prescribed value and a desired photoelastic constant corresponding to the value of the molar ratio can be obtained. the photoelastic constant of the glass can be set at a desired value according to applications.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass having a predetermined photoelastic constant such as a low photoelastic glass used as a Faraday element for a polarization optical system or an optical current transformer. The present invention relates to a glass capable of realizing a low refractive index and a method for producing the same.

[0002]

2. Description of the Related Art In recent years, as a polarization optical system such as a spatial light modulation element or a polarization beam splitter of a liquid crystal projector, or as a Faraday element in an optical current transformer for measuring a current of a conductor to be measured by utilizing the Faraday effect. Glass is attracting attention. However, in the case of glass, when mechanical stress or thermal stress is applied by external force or heat, stress distortion occurs, and the glass exhibits birefringence due to the photoelastic effect. There is a problem that it is difficult to obtain or the measured value of the optical current transformer varies.

[0003] The magnitude of birefringence in glass appears as an optical path difference, and the greater the birefringence, the greater the optical path difference. Here, the optical path difference is δ, the thickness of the glass is d, and the stress is F.
Then, the relational expression of δ = β · d · F holds. The proportionality constant β in the above equation
Is called a photoelastic constant, which is a specific value for each glass material.If this photoelastic constant is small, the optical path difference, that is, the birefringence, is reduced for the same stress, and the adverse effect of birefringence is also suppressed. Can be In recent years, glass having a small photoelastic constant has been developed for applications such as the above-mentioned polarizing optical system and Faraday element, and glass having a high lead content is most commonly used as such a glass having a small photoelastic constant. ing.

Another example of glass having a small photoelastic constant is described in Japanese Patent Application Laid-Open No. 2000-34132. This other conventional glass is mainly
41-52% phosphorus pentoxide, 47-57 barium oxide
%, And 0.5 to 5% of alumina, and has a photoelastic constant of 0.5 × 10 ⁻¹² [1 / Pa] or less.

[0005]

The conventional glass is constituted as described above. A glass having a high lead content containing 70% or more by weight of lead has a photoelastic constant to a level that does not cause a practical problem. Although small, the refractive index becomes extremely high, and due to this high refractive index, there is a problem that it is difficult to be compatible with existing optical materials such as a quartz glass material and a matching oil. Further, when the refractive index is large, the minimum value (lower limit) of the current sensitivity becomes large when used as a Faraday element, and the sensitivity adjustment by the number of turns becomes difficult. Furthermore, although the latter glass containing phosphorus pentoxide, barium oxide, and alumina has a low refractive index, it has a problem that the photoelastic constant remains relatively large as compared with a glass having a high lead content. I was

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a glass and a method of manufacturing the glass, which can set a photoelastic constant appropriately, achieve both a low refractive index and a low photoelasticity, and are easy to manufacture. The purpose is to provide.

[0007]

The glass according to the present invention comprises:
The photoelastic constant is obtained as a function of the molar ratio between the network modifying component containing at least an element having high ion polarization and the network forming component. Thus, in the present invention,
The photoelastic constant is given as a function of the molar ratio between the network modifying component and the network forming component, and when the molar ratio between the network modifying component and the network forming component is determined, the photoelastic constant is determined. The raw materials are appropriately adjusted so that the molar ratio with the components becomes a predetermined value, and a desired photoelastic constant corresponding to the value of the molar ratio can be obtained. Can be set.

In the glass according to the present invention, if necessary, the network modifying component is barium oxide, and the network forming component is phosphorus pentoxide. Thus, in the present invention, while the network modifying component is barium oxide, the network forming component is phosphorus pentoxide, and the ratio of barium oxide having a property of reducing the photoelastic constant is adjusted to a predetermined photoelastic constant. By doing so, the photoelastic constant can be easily reduced by increasing the molar ratio of barium oxide.

In the glass according to the present invention, the multiplier of the molar ratio in the linear function among the functions defining the photoelastic constant may be -1.13 × 10 ^-12 ± 0.06 × 1 if necessary.
0 ⁻¹² and the constant term is 1.59 × 10 ⁻¹² ± 0.0
It is 5 × 10 ⁻¹² . As described above, in the present invention, when the photoelastic constant is a linear function of the molar ratio between the network modifying component and the network forming component, the multiplier of the molar ratio and the constant term in this linear function are respectively -1.13 × 10
^-12 ± 0.06 × 10 ^-12 , 1.59 × 10 ^-12 ± 0.0
Given a 5 × 10 ^-12, moles of by photoelastic constant is required when determining the molar ratio of the network-modifying component and network formers, and the desired network-modifying component for realizing a photoelastic constant and network formers The ratio can be easily derived, and the molar ratio can be adjusted to the raw material to produce an arbitrary photoelastic constant.

The glass according to the present invention contains 0 to 7% of fluorine as necessary, and the molar ratio between the network modifying component and the network forming component is 1.25 or more. As described above, in the present invention, after adding a trace amount of fluorine, the ratio of the network modifying component is increased to increase the molar ratio to 1.25 or more, and the behavior of the raw material melt during production is stabilized by fluorine. The transition to the glass state without hindrance results in a clean glass state without quality deterioration such as crystallization, and the photoelastic constant can be reliably reduced as the number of moles of the network modifying component increases.

Further, the glass according to the present invention has a refractive index of 1.65 or less and a photoelastic constant of 0.3 [× 10 ⁻¹² (1 / Pa)] or less, if necessary. is there. As described above, in the present invention, by setting the refractive index and the photoelastic constant to be smaller than a predetermined value, in addition to suppressing the birefringence, the compatibility with the existing optical material due to the low refractive index is improved. It can be expanded, and also when used as a sensor material, the minimum value of the current sensitivity becomes small, and the sensitivity adjustment by the number of turns becomes easy.

If necessary, the glass according to the present invention has a photoelastic constant of 0.018 × 10 ⁻¹² ± 10 as a multiplier with respect to the fluorine content (mol%).
It is obtained by adding a value multiplied by 0.005 × 10 ⁻¹² to the constant term of the linear function. As described above, in the present invention, when fluorine containing the property of increasing the photoelastic constant is contained, the fluorine content that achieves the desired photoelastic constant can be obtained by determining the photoelastic constant in consideration of the fluorine content. Can be easily obtained, and a desired photoelastic constant can be obtained by adjusting the fluorine content by the amount added.

If necessary, the glass according to the present invention has a photoelastic constant of 0.010 × 10 ⁻¹² as a multiplier to the alumina content (mol%) when alumina is contained.
It is obtained by adding a value multiplied by ± 0.005 × 10 ⁻¹² to the constant term of the linear function. As described above, in the present invention, a desired photoelastic constant is realized by obtaining a photoelastic constant in consideration of the alumina content when alumina having a property of enhancing the photoelastic constant is contained as an additive or impurity. The content of alumina to be obtained can be easily derived, and a desired photoelastic constant can be obtained by manufacturing while adjusting the alumina content by the added amount. In addition, characteristic values such as a refractive index can be adjusted by adding alumina.

Further, in the glass production method according to the present invention, the network modifying component in a vitrified state and one or a plurality of starting materials containing each element serving as a network forming component are used as a glass raw material, and the network modifying component is increased. Fluoride of high ionic polarizable element contained in the network modifying component as additive material for
Fluoride and oxide of the high ionic polarizable element, or
A predetermined fluoride and an oxide of the highly ionic polarizable element are added in a predetermined amount. As described above, in the present invention, a substance containing a high ionic polarizable element or fluorine contained in the network modifying component is added as an additive material for increasing the ratio of the network modifying component in the vitrified state, and a small amount of fluorine is added to the raw material melt. While the state where is contained, by increasing the molar ratio of the network modifying component, the behavior of the raw material melt at the time of production can be stabilized by fluorine and transferred to a glass state,
Crystallization and the like can be prevented to obtain a clean glass state without quality deterioration, and a glass having a small photoelastic constant by increasing the molar ratio of the network modifying component can be reliably produced.

The glass manufacturing method according to the present invention uses barium metaphosphate as the starting material and adds barium fluoride as the additive material as needed. As described above, in the present invention, barium metaphosphate is used as a starting material, barium fluoride is added as an additive material for increasing the ratio of barium oxide, which is a network modifying component in a vitrified state, and a small amount of fluorine is added to the raw material melt. While increasing the molar ratio of barium oxide, the behavior of the raw material melt during production can be stabilized with fluorine and transferred to the glass state without hindrance, thereby increasing the molar ratio of barium oxide. Can be made into a clean glass state without quality deterioration such as crystallization, and it is possible to reliably produce glass with a reduced photoelastic constant by increasing the molar ratio of barium oxide. Further, the refractive index of the manufactured glass can be reduced.

Further, in the glass manufacturing method according to the present invention, if necessary, the starting material is heated and melted, a predetermined gas reacting with fluorine is blown into the raw material melt, and the fluorine in the raw material melt is reduced to the predetermined temperature. It reacts with a gas and volatilizes from the raw material melt in the state of a fluoride gas. As described above, in the present invention, by blowing a predetermined gas that reacts with fluorine after the starting material is melted to volatilize fluorine as a fluoride gas, and reducing the amount of fluorine in the material melt, a glassy state is obtained. The adverse effect due to the presence of fluorine can be suppressed, and a glass with clean and improved homogeneity can be manufactured. In addition, the photoelastic constant of the glass can be further reduced by reducing the amount of fluorine.

Further, according to the glass production method of the present invention, if necessary, after blowing wet air as the predetermined gas into the raw material melt obtained by heating and melting the starting material, chlorine or chlorine is introduced into the raw material melt. Chloride is added, water in the raw material melt is reacted with chlorine or chloride, and the generated hydrogen chloride is volatilized from the raw material melt. As described above, in the present invention, after the starting material is melted and moist air is blown, chlorine or chloride is further added to the raw material melt to react with water remaining in the raw material melt to form water. Hydrogen chloride is converted to hydrogen chloride and volatilized out of the raw material melt, and the amount of water contained in the raw material melt is reduced, thereby reducing the adverse effects of water in the glass state and improving cleanliness and homogeneity. Further improved glass can be produced.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below.
I will tell. The glass according to the present embodiment has a network modifying component and
And a photoelastic constant of the network modifying component.
Obtained as a linear function of the molar ratio of
Things. The linear function that defines this photoelastic constant is
The multiplier of the molar ratio is -1.13 (× 10 ^-12) And the constant
Term is 1.59 (× 10^-12). Glass
The molar ratio between the network modifying component and the network forming component in
If X and the photoelastic constant of glass are Y, the relationship is
It is represented by Y [× 10^-12(1 / Pa)] =-1.13X + 1.5
9

Barium oxide (BaO) and lead oxide (P) are used as the network modifying components in the glass according to the present embodiment.
bO) and the like, preferably barium oxide. Further, as a network forming component, phosphorus pentoxide (P
₂ O ₅ ), silicon dioxide (SiO ₂ ) and the like, preferably phosphorus pentoxide. In addition, as substances added to the basic composition for chemical durability, thermal stability, refractive index adjustment, formation of high-grade glass, etc., Al ₂ O ₃ , La ₂ O ₃ ,
Nb ₂ O ₅ , Sb ₂ O ₃ , Na ₂ O, CaO, K ₂ O, Sn
O, TiO ₂ , B ₂ O ₃ and the like. Further, in order to increase the ratio of the network modifying component, a fluoride or the like of an element having high ionic polarization included in the network modifying component may be added. In addition, alumina (Al ₂ O ₃ ) may be added as an impurity due to elution from the alumina crucible.

When fluorine or alumina is contained in the glass, if the fluorine content (mol%) is C and the alumina content (mol%) is D, the photoelastic constant Y of the glass can be obtained by the following equation. . Y [× 10 ⁻¹² (1 / Pa)] = − 1.13X + 0.0
18C + 0.010D + 1.59 When the molar ratio X becomes 1.25 or more, the refractive index becomes 1.
65 or less and the photoelastic constant is 0.3 [× 10 ^-12 (1
/ Pa)] The following glass is obtained.

Next, a method for manufacturing glass according to the present embodiment will be described. In this method for producing glass, one or more predetermined starting materials containing elements constituting the network modifying component and the network forming component are used, and the molar ratio between the network modifying component and the network forming component when the glass is formed is reduced. An additive material is appropriately added and adjusted so as to have a desired ratio. Further, in order to increase the ratio of the network modifying component, a fluoride of an element having high ionic polarization included in the network modifying component (for example,
Barium fluoride), an oxide of the same highly ionic polarizable element (for example, barium oxide) together with the fluoride, or a fluoride of another predetermined element together with the oxide of the highly ionic polarizable element. (For example, calcium fluoride or magnesium fluoride) in some cases.

After the starting material is melted, fluorine generated from the added fluoride is present in the raw material melt. When moist air is blown into the raw material melt and the water in the air is reacted with the fluorine in the raw material melt, the fluorine becomes hydrogen fluoride. Due to the volatilization of the hydrogen fluoride from the raw material melt, only fluorine is reduced from the raw material melt. Subsequently, when chlorine gas or barium chloride is added to the raw material melt and chlorine contained therein is reacted with moisture in the raw material melt, hydrogen forming water becomes hydrogen chloride. The hydrogen chloride is volatilized in a gaseous state from the raw material melt, and the water content is reduced from the raw material melt. Thereafter, the raw material melt is homogenized by stirring, aeration, and the like, and further cooled in a mold to obtain glass.

Thus, in the glass according to the present embodiment, the photoelastic constant is given as a linear function of the molar ratio,
Since the photoelastic constant is easily determined when the molar ratio between the network modifying component and the network forming component is determined, the raw materials are appropriately adjusted so that the molar ratio between the network modifying component and the network forming component becomes a predetermined value, and the molar ratio is adjusted. A desired photoelastic constant corresponding to the value of the ratio can be obtained, and the photoelastic constant of the glass can be set to a desired value depending on the application. Further, after adding a small amount of fluorine, the molar ratio is increased by increasing the ratio of the network modifying component to 1.
When the raw materials are adjusted to be higher than 25, the behavior of the raw material melt at the time of production can be stabilized with fluorine and can be shifted to a glass state without any trouble, and a clean glass state without quality deterioration is obtained, and the As the number of moles increases, the photoelastic constant can be reliably reduced. Furthermore, when fluorine or alumina having the property of increasing the photoelastic constant is contained, the photoelastic constant in consideration of these contents can be obtained, so that the content of fluorine or alumina that achieves the desired photoelastic constant is reduced. Easy to guide,
A desired photoelastic constant can be obtained by adjusting the content of fluorine and / or alumina by adjusting the content.

[0024]

EXAMPLE The evaluation results of the photoelastic constant of the glass manufactured by the glass manufacturing method according to the present invention, and the comparison of the photoelastic constant, the refractive index, and the current sensitivity with the lead glass manufactured by the same composition and manufacturing method as before were compared. The evaluation results obtained will be described.

In the present embodiment, barium metaphosphate (BaO) is used as a starting material of the basic composition so that barium oxide (BaO) is produced as a network modifying component and phosphorus pentoxide (P ₂ O ₅ ) is produced as a network forming component. Glass production is performed using Ba (PO ₃ ) ₂ ). The molar ratio between BaO and P ₂ O ₅ when glass is used as the starting material is 1.0. In addition, barium fluoride (BaF ₂ ) is mixed as an additive, and barium oxide (Ba
Adjust the proportion of O).

The glass according to the present invention is made of barium oxide (B
aO) and phosphorus pentoxide (P ₂ O ₅ ) are produced at different molar ratios, and the photoelastic constants are compared. As a first embodiment, barium fluoride is added as an additive to barium metaphosphate as a starting material, and the molar ratio of barium oxide to phosphorus pentoxide to be produced is adjusted. The composition was 51.6% of barium oxide and 3% of phosphorus pentoxide in mol% based on the whole glass.
9.1%, 2.6% fluorine, 2.5% sodium oxide
%, And 0.5% of alumina and 2.3% of silicon dioxide as impurities. In addition, very small amounts of magnesium oxide and potassium oxide are also contained.

Next, as a second embodiment, the addition ratio of barium fluoride to barium metaphosphate was changed,
A glass was obtained in the same manner as in Example. The composition was 53.9% of barium oxide, 39.2% of phosphorus pentoxide, 1.9% of fluorine, 1.4% of sodium oxide, and 0.5% of alumina as an impurity in mol% based on the whole glass. %,
Silicon dioxide is 2.8%. In addition, very small amounts of magnesium oxide and potassium oxide are also contained. The composition of the glass in each of the above examples is summarized in the upper part of Table 1.

[0028]

[Table 1]

Glass was manufactured by the glass manufacturing method of the present invention based on the composition of each example. After melting of barium metaphosphate as a starting material and barium fluoride as an additive, fluorine generated from the added barium fluoride is present in the raw material melt. When moist air is blown into the raw material melt and the water in the air is reacted with the fluorine in the raw material melt, the fluorine becomes hydrogen fluoride. Due to the volatilization of the hydrogen fluoride from the raw material melt, only fluorine is reduced from the raw material melt.

Subsequently, chlorine gas is blown into the raw material melt,
When chlorine reacts with the water in the raw material melt, hydrogen that forms water becomes hydrogen chloride. The hydrogen chloride is volatilized in a gaseous state from the raw material melt, and the water content is reduced from the raw material melt. After this,
The raw material melt is stirred and homogenized, and then gradually cooled in a mold to obtain a glass.

An evaluation test was performed on the glass produced as described above for the refractive index and the photoelastic constant. In the test, the actual values of the refractive index and the photoelastic constant were measured, respectively. The measured values in this test are shown in the lower part of Table 1.
In addition, the photoelastic constant obtained by the calculation formula from the molar ratio and the addition ratio of each additive is also shown. The photoelastic constant is He-
It is obtained by measuring the optical path difference generated at the center of the glass when a compressive load is applied in a predetermined direction to glass having a diameter of 10 mm and a length of 10 mm using Ne laser light. The refractive index is for visible light having a wavelength of 632.8 nm.

As shown in Table 1, the photoelastic constant of Example 1 was 0.15 [× 10 ⁻¹² (1 / Pa)],
Example 2 ^{0.08 [× 10 -12 (1 /} Pa)] , and the no practical problems ^{0.2 [× 10 -12 (1 /} P
a)] are obtained. On the other hand, the refractive index of Example 1 and Example 2 is 1.60, which is a sufficiently low value as compared with lead glass having the same photoelastic constant.

Thus, barium fluoride is added as an additive to barium metaphosphate as a basic material, and the raw material adjusted so that the molar ratio of barium oxide to phosphorus pentoxide becomes 1.3 or more is melted. By using the production method of the present invention to volatilize and remove most of fluorine from,
It was confirmed that a glass having a high molar ratio of barium oxide and a low photoelastic constant and refractive index could be obtained. Further, the measured photoelastic constants of Examples 1 and 2 and the calculated photoelastic coefficient were almost the same, and from the relationship between the photoelastic constant and the molar ratio, the photoelastic constant was a linear function of the molar ratio. It was confirmed that it was expressed. Further, evaluation results of comparing the glass of the present example with a lead glass manufactured by the same composition and manufacturing method as those of the related art in terms of photoelastic constant, refractive index, and current sensitivity will be described. Table 2 shows the evaluation results.

[0034]

[Table 2]

In the glass according to the present invention having almost the same photoelastic constant as lead glass, the refractive index is sufficiently lower than that of lead glass, and accordingly, the current when used as a Faraday element of an optical current transformer is correspondingly increased. The sensitivity is also excellent.
That is, the refractive index is a value related to the current sensitivity when used as a Faraday element (optical fiber for a sensor). When the refractive index is small, the resolution (minimum value) of the current sensitivity is small, and the sensitivity due to the number of turns in the sensor configuration is small. Adjustment is easy and suitable for large current measurement. In addition to the low photoelastic constant and low birefringence, as well as the low refractive index, applications where bending stress is generated in materials, such as bonding to quartz fibers and matching oil in optical fibers, etc. The range of compatibility with existing optical materials is greatly expanded, and the connectivity is greatly improved.

[0036]

As described above, according to the present invention, the photoelastic constant is given as a function of the molar ratio between the network modifying component and the network forming component, and the molar ratio between the network modifying component and the network forming component is determined. When the photoelastic constant is determined, the raw material can be appropriately adjusted so that the molar ratio between the network modifying component and the network forming component becomes a predetermined value, and a desired photoelastic constant corresponding to the value of the molar ratio can be obtained. This has the effect that the photoelastic constant of the glass can be set to a desired value depending on the application. Further, according to the present invention, while the network modifying component is barium oxide, the network forming component is phosphorus pentoxide, and the ratio of barium oxide having a property of reducing the photoelastic constant is adjusted to a predetermined photoelastic constant. By doing so, there is an effect that the photoelastic constant can be easily reduced by increasing the molar ratio of barium oxide.

According to the present invention, when the photoelastic constant is a linear function of the molar ratio between the network modifying component and the network forming component, the multiplier of the molar ratio and the constant term in this linear function are respectively -1.13. × 10 ^-12 ± 0.06 × 10 ^-12 ,
Given a value of 1.59 × 10 ⁻¹² ± 0.05 × 10 ⁻¹² , a desired photoelastic constant is realized by obtaining a photoelastic constant when the molar ratio between the network modifying component and the network forming component is determined. There is an effect that the molar ratio between the network modifying component and the network forming component can be easily derived, and it is possible to obtain an arbitrary photoelastic constant by manufacturing while adjusting the molar ratio with the raw material.
Further, according to the present invention, by adding a trace amount of fluorine, increasing the ratio of the network modifying component to increase the molar ratio to 1.25 or more, and stabilizing the behavior of the raw material melt during production with fluorine. The transition to the glass state without hindrance results in a clean glass state without quality deterioration such as crystallization, and the photoelastic constant can be reliably reduced as the number of moles of the network modifying component increases. Has an effect.

Further, according to the present invention, by setting the refractive index and the photoelastic constant to be smaller than a predetermined value, the birefringence can be suppressed, and in addition to the low refractive index, the existing optical material can be used. The suitability can be expanded, and also when used as a sensor material, the minimum value of the current sensitivity is reduced, and the sensitivity can be easily adjusted by the number of turns. Further, according to the present invention, when fluorine having a property of increasing the photoelastic constant is contained, the photoelastic constant in consideration of the fluorine content can be obtained, so that the fluorine content that achieves a desired photoelastic constant can be obtained. Can be easily obtained, and it is possible to produce a desired photoelastic constant by adjusting the fluorine content by adjusting the content.

Further, according to the present invention, when alumina having a property of enhancing the photoelastic constant is contained as an additive or an impurity, the photoelastic constant taking into account the alumina content can be obtained, whereby a desired photoelastic constant can be obtained. There is an effect that the content of alumina for realizing the constant can be easily derived, and a desired photoelastic constant can be obtained by manufacturing while adjusting the alumina content by the added amount. Further, there is an effect that characteristic values such as a refractive index can be adjusted by adding alumina. According to the present invention, a substance containing a highly ion-polarizable element or fluorine contained in the network modifying component is added as an additive material for increasing the ratio of the network modifying component in the vitrified state, and a small amount of fluorine is added to the raw material melt. While being included,
By increasing the molar ratio of the network modifying component and stabilizing the behavior of the raw material melt during production with fluorine and transferring it to the glass state, it is possible to prevent crystallization etc. and make it a clean glass state without deterioration in quality In addition, it is possible to reliably produce a glass having a small photoelastic constant by increasing the molar ratio of the network modifying component.

Further, according to the present invention, barium metaphosphate is used as a starting material, barium fluoride is added as an additive material for increasing the ratio of barium oxide, which is a network modifying component in a vitrified state, and the raw material melt is added. By increasing the molar ratio of barium oxide while keeping a small amount of fluorine contained, the behavior of the raw material melt during production can be stabilized by fluorine and transferred to the glass state without hindrance. However, even if the value is increased, a clean glass state without quality deterioration such as crystallization can be obtained, and the glass having a reduced photoelastic constant by increasing the molar ratio of barium oxide can be produced reliably.
Further, there is an effect that the refractive index of the manufactured glass can be reduced.

In addition, according to the present invention, a predetermined gas that reacts with fluorine after the starting material is melted is blown to volatilize fluorine as a fluoride gas, thereby reducing the amount of fluorine in the material melt, thereby reducing the amount of fluorine in the raw material melt. The effect of suppressing the adverse effect of the presence of fluorine in the state can produce a glass with clean and improved homogeneity, and the effect of reducing the fluorine can further reduce the photoelastic constant of the glass. Further, according to the present invention, after the starting material is melted and humid air is blown, chlorine or chloride is further added to the raw material melt to react with water remaining in the raw material melt to form water. Hydrogen to hydrogen chloride and volatilize outside the raw material melt,
By reducing the amount of water contained in the raw material melt, an adverse effect due to the presence of water in a glass state can be suppressed, and an effect that a glass with clean and further improved homogeneity can be produced.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kenji Morinaga 6-1, Kasuga Park, Kasuga City, Fukuoka Prefecture Kyushu University F-term (reference) 4G062 AA04 BB01 BB09 CC04 CC10 DA03 DB02 DC01 DD05 DE01 DF01 EA01 EB03 EC01 EC02 ED01 ED02 EE01 EF01 EG06 FA01 FA10 FB01 FC01 FD01 FE01 FF01 FG01 FH01 FJ01 FK01 FL01 GA01 GB01 GC01 GD01 GE03 HH01 HH03 HH05 HH07 HH09 HH11 HH13 HH15 HH17 HH20 JJ01 JJ03 KK05 KK05 KK07 KK10

Claims (11)

[Claims] 1. A glass characterized in that the photoelastic constant is obtained as a function of the molar ratio between a network modifying component containing at least an element having high ionic polarization and a network forming component. 2. The glass according to claim 1, wherein the network modifying component is barium oxide, and the network forming component is phosphorus pentoxide. 3. The glass according to claim 1, wherein a multiplier of a molar ratio in a linear function among functions defining a photoelastic constant is −1.13 × 10 ⁻¹² ± 0.06 × 10 ^−12.
And the constant term is 1.59 × 10 ^-12 ± 0.05 ×
A glass characterized by being ^10-12 . 4. The glass according to claim 1, wherein the glass contains 0 to 7% of fluorine, and the molar ratio between the network modifying component and the network forming component is 1.25 or more. Glass. 5. The glass according to claim 4, which has a refractive index of 1.65 or less and a photoelastic constant of 0.3.
A glass characterized by being not more than [× 10 ⁻¹² (1 / Pa)]. 6. The glass according to claim 4, wherein the photoelastic constant in the case of containing fluorine is 0.018 × 10 ⁻¹² ± 0.0 as a multiplier of the fluorine content (mol%).
A glass obtained by adding a value multiplied by 05 × 10 ⁻¹² to a constant term of the linear function. 7. The glass according to any one of claims 1 to 6, wherein a photoelastic constant when alumina is contained is 0.010 × 10 ^-12 ± as a multiplier of the alumina content (mol%).
Glass obtained by adding a value multiplied by 0.005 × 10 ⁻¹² to the constant term of the linear function. 8. A glass-modified state in which one or a plurality of starting materials containing each element serving as a network-modifying component and a network-forming component in a vitrified state are used as glass raw materials, and are included in the network-modifying component as additive materials for increasing the network-modifying component. A glass characterized by adding a predetermined amount of a fluoride of the high ionic polarization element, a fluoride and an oxide of the high ionic polarization element, or a predetermined fluoride and an oxide of the high ionic polarization element Production method. 9. The glass manufacturing method according to claim 8, wherein barium metaphosphate is used as the starting material, and barium fluoride is added as the increasing additive material. 10. The glass manufacturing method according to claim 8 or 9, wherein the starting material is heated and melted, and a predetermined gas that reacts with fluorine is blown into the raw material melt to reduce the fluorine in the raw material melt. A glass production method characterized by reacting with a predetermined gas and volatilizing from a raw material melt in a state of a fluoride gas. 11. The glass manufacturing method according to claim 10, wherein after blowing the humid air as the predetermined gas into the raw material melt obtained by heating and melting the starting raw material, chlorine or chloride is added to the raw material melt. A glass production method, comprising adding a substance, reacting water in the raw material melt with chlorine or chloride, and volatilizing generated hydrogen chloride from the raw material melt.