Glass material manufacturing method

Abstract

To provide a method for producing a glass material having high light transmittance.SOLUTION: The present invention provides a method for manufacturing a glass material, which is a paramagnetic glass material, the method comprising: a step for adding CeO2 to a glass raw material containing FeO and / or Fe2O3; and a melting step for melting the CeO2-added glass raw material in a vacuum atmosphere, an inert atmosphere, or a reducing atmosphere.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to a method for manufacturing glass materials. [Background technology]

[0002] Paramagnetic glass materials are known to exhibit the Faraday effect, a magneto-optical effect. The Faraday effect is the rotation of linearly polarized light passing through a material placed in a magnetic field. Magneto-optical elements that utilize this effect (e.g., Faraday rotators) are used in magneto-optical devices such as optical isolators.

[0003] Examples of paramagnetic glass materials include the SiO2-B2O3-Al2O3-Tb2O3 system (Patent Document 1) and the P2O5-B2O3-Tb2O3 system (Patent Document 2). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Special Publication No. 51-46524 [Patent Document 2] Special Publication No. 52-32881 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] In recent years, the laser light irradiated onto magneto-optical devices has been increasing in power. As the laser light output increases, the temperature of the magneto-optical element rises, making it more susceptible to beam diameter changes due to the thermal lensing effect. Therefore, improving the light transmittance of the magneto-optical element is required to reduce the thermal lensing effect.

[0006] In view of the above, the present invention aims to provide a method for manufacturing a glass material with high light transmittance. [Means for solving the problem]

[0007] The present invention relates to a method for manufacturing a glass material, wherein the glass material is a paramagnetic glass material, and comprises a step of adding CeO2 to a glass raw material containing FeO and / or Fe2O3, and a melting step of melting the glass raw material added with CeO2 in a vacuum atmosphere, an inert atmosphere or a reducing atmosphere.

[0008] In the method for manufacturing a glass material of the present invention, the addition amount of CeO2 is preferably 0.001% to 1% in mol% on an external basis.

[0009] In the method for manufacturing a glass material of the present invention, the paramagnetic glass material is preferably a Tb2O3-based glass material.

[0010] In the method for manufacturing a glass material of the present invention, the Tb2O3-based glass material preferably contains, in mol%, 10% to 90% of Tb2O3, 1% to 89% of B2O3 + Al2O3 + SiO2 + P2O5, 0.01 ppm to 100 ppm of FeO + Fe2O3, and further preferably contains 0.001% to 1% of CeO2 on an external basis.

[0011] In the method for manufacturing a glass material of the present invention, in the melting step, Fe 2+ is oxidized to Fe 3+ , and Tb 4+ is preferably reduced to Tb 3+ .

[0012] In the method for manufacturing a glass material of the present invention, the glass raw material is preferably a precursor glass.

[0013] In the method for manufacturing a glass material of the present invention, it preferably further comprises a step of melting a glass raw material excluding CeO2 to prepare a precursor glass material.

[0014] In the method for manufacturing a glass material of the present invention, the ratio of Tb 3+ to the total Tb of the glass material is preferably 55% or more in mol%.

[0015] In the method for manufacturing a glass material of the present invention, the light transmittance of the glass material at a wavelength of 532 nm is preferably 70% or more. [Effects of the Invention]

[0016] According to the present invention, it is possible to provide a method for manufacturing a glass material with high light transmittance. [Modes for carrying out the invention]

[0017] The present invention relates to a method for manufacturing a glass material, characterized in that the glass material is a paramagnetic glass material, and comprises the steps of adding CeO2 to a glass raw material containing FeO and / or Fe2O3, and melting the glass raw material to which CeO2 has been added in a vacuum atmosphere, an inert atmosphere, or a reducing atmosphere. In the following description, unless otherwise specified, "%" means "mol%". In the following description, "visible to near-infrared wavelength range" refers to the wavelength range used for visible to near-infrared lasers, and unless otherwise specified, it refers to the wavelength range of 300 nm to 2000 nm, and especially 300 nm to 1100 nm.

[0018] The glass material manufacturing method of the present invention is suitable for the manufacture of paramagnetic glass materials. Paramagnetic glass materials may change in properties (e.g., light transmittance) due to changes in the valence of their constituent components caused by oxidation. Therefore, using the manufacturing method of the present invention makes it easier to suppress excessive oxidation and prevent changes in properties for reasons described later. Paramagnetic glass materials are not particularly limited, but examples include Tb2O3-based glass materials, Pr2O3-based glass materials, and EuO-based glass materials.

[0019] <Preparation of glass raw materials> First, a glass raw material having the desired paramagnetic glass composition is prepared. The glass raw material contains FeO and / or Fe2O3. In the present invention, raw material powders such as natural raw materials and chemical raw materials, or glass materials obtained by melting and vitrifying these (hereinafter referred to as precursor glass materials), can be used as the glass raw material, but for reasons described later, it is preferable to use precursor glass materials.

[0020] FeO and Fe2O3 are components that reduce the light transmittance in the visible to near-infrared wavelength range and tend to cause a thermal lens effect. Specifically, FeO (Fe 2+ ) has a broad absorption peak around a wavelength of 1200 nm. Therefore, the glass material absorbs laser light in the visible to near-infrared wavelength range and generates heat, making it easy for the thermal lens effect to occur. In addition, Fe2O3 (Fe 3+ ) may be reduced to FeO during the melting process. Therefore, the content of FeO + Fe2O3 (the total amount of FeO and Fe2O3) is 0.01 ppm to 100 ppm, preferably 0.01 ppm to 20 ppm, 0.05 ppm to 15 ppm, 0.1 ppm to 14 ppm, 0.2 ppm to 13 ppm, 0.3 ppm to 11 ppm, 0.4 ppm to 10 ppm, 0.5 ppm to 9 ppm, and particularly preferably 1 ppm to 8 ppm. If the content of FeO + Fe2O3 is too low, the manufacturing cost is likely to increase.

[0021] Next, CeO2 is added to the glass raw material. CeO2 is a component that functions as an oxidizing agent. This makes it easier to suppress the reduction in light transmittance caused by FeO and / or Fe2O3. Specifically, CeO2 oxidizes Fe 2+ in the glass to Fe 3+ and is likely to suppress light absorption at wavelengths of 300 nm to 1100 nm. Therefore, it becomes easier to obtain a glass material with high light transmittance. In addition, because the light transmittance of the glass material is high, it becomes easier to suppress the deformation of the laser beam profile due to the thermal lens effect.

[0022] The addition amount of CeO2 is preferably 0.001% to 1%, 0.01% to 1%, 0.05% to 0.9%, 0.1% to 0.8%, and particularly preferably 0.1% to 0.7% in mol%. If the addition amount of CeO2 is too small, the effect of oxidizing Fe 2+ in the glass to Fe 3+ becomes small. If the addition amount of CeO2 is too large, the molten glass is likely to be overly oxidized, and conversely, the light transmittance of the glass material is likely to decrease. For example, when Tb 3+ is oxidized to Tb 4+ , by this, Tb4+ This can easily lead to a decrease in the light transmittance of the glass material. Note that the above-mentioned additive amount refers to the value added externally to the glass raw material. In other words, in mole percent, it means that the CeO2 content is 0.001% to 1% (i.e., the total amount is 100.001% to 101%) relative to 100% of the total content of components other than CeO2.

[0023] The ratio of CeO2 added (content) to FeO+Fe2O3 content, CeO2 / (FeO+Fe2O3), is preferably 10-10000, 30-10000, 100-7500, 100-5000, and especially 100-3000. By satisfying the above ratios for CeO2 added (content) and FeO+Fe2O3 content, the thermal lensing effect is more easily suppressed.

[0024] <Melting process> Next, the glass raw material to which CeO2 has been added is melted to obtain a glass material. The melting atmosphere is a vacuum atmosphere, an inert atmosphere, or a reducing atmosphere, with an inert atmosphere being particularly preferred. This suppresses excessive oxidation of the molten glass and makes it easier to suppress the decrease in the light transmittance of the glass material. The atmosphere used when cooling and solidifying the molten glass can be any of air, a vacuum atmosphere, an inert atmosphere, or a reducing atmosphere, but from the viewpoint of facilitating manufacturing, an air atmosphere is preferred.

[0025] In the melting process, the melting time is preferably 3 hours or more, 4 hours or more, and particularly 5 hours or more. It is also preferable that it be 15 hours or less, 10 hours or less, and particularly 9 hours or less. If the melting time is too short, the clarity of the molten glass will be insufficient, and a large amount of residual bubbles will tend to form. If the melting time is too long, the components of the melting vessel will tend to dissolve into the molten glass. For example, when melting glass raw materials using a platinum crucible, fine Pt particles may form in the molten glass, which can easily reduce the light transmittance of the glass material. Also, when melting glass raw materials using a quartz crucible, SiO2 may dissolve into the molten glass, making it difficult to obtain a glass material with the desired composition.

[0026] In the melting process, it is preferable to melt the glass raw material using a melting container. The melting container is preferably made of platinum or a platinum alloy on the surface that comes into contact with the molten glass. For example, it is preferable to use a platinum crucible, a platinum-rhodium crucible, a reinforced platinum crucible, or a melting furnace lined with platinum or a platinum alloy as the melting container. A quartz crucible may also be used. Alternatively, the glass raw material may be melted using a so-called containerless levitation method, without the use of a melting container.

[0027] It is preferable to anneal the obtained glass material. This removes any distortion from the glass material. The annealing atmosphere can be an air atmosphere, a reducing atmosphere, or an inert atmosphere, but from the viewpoint of facilitating manufacturing, it is preferable to carry it out in an air atmosphere.

[0028] Thus, the present invention's method for manufacturing glass materials involves adding CeO2, which functions as an oxidizing agent, to the glass raw material and melting the glass raw material in a vacuum atmosphere, an inert atmosphere, or a reducing atmosphere. This configuration makes it possible to suppress excessive oxidation of the molten glass. As a result, in the production of Tb2O3-based glass materials, Fe 2+ Fe 3+ While oxidizing, Tb 3+ Tb 4+ This can suppress oxidation.

[0029] The oxidation-reduction phenomenon in this invention will be described in detail as follows. Firstly, by adding CeO2 to the glass raw material, the Fe contained in the glass is reduced. 2+ Fe 3+ This causes the Fe 2+ This makes it easier to suppress light absorption in the wavelength range of 300 nm to 1100 nm caused by the following. Secondly, by melting the glass raw material with added CeO2 in a vacuum atmosphere, an inert atmosphere, or a reducing atmosphere, excessive oxidation of the molten glass is suppressed. For example, in a paramagnetic glass material such as Tb2O3 glass material, Tb 3+ Tb 4+ This suppresses oxidation of Tb. 4+This makes it easier to suppress light absorption in the wavelength range of 300 nm to 1100 nm caused by the present invention. In other words, according to the glass material manufacturing method of the present invention, Fe having absorption in the visible to near-infrared wavelength range 2+ and Tb 4+ This allows for a reduction in the content of certain substances, making it possible to manufacture glass materials with high light transmittance.

[0030] <Precursor glass material manufacturing process> In the glass material manufacturing method of the present invention, it is preferable to use a precursor glass material as the glass raw material. This makes it easier to obtain a highly homogeneous glass material. In this invention, the precursor glass material refers to glass cullet in which the components other than CeO2 are equivalent in component ratio to the target glass material.

[0031] Precursor glass materials can be manufactured by mixing glass raw materials to achieve a predetermined glass composition and then melting the glass raw materials. The following describes preferred conditions for the precursor glass material manufacturing process.

[0032] In the precursor glass material manufacturing process, the melting time is preferably less than 3 hours, 2 hours or less, and particularly 1 hour or less. It is also preferable that the melting time be 5 minutes or more, 10 minutes or more, and particularly 20 minutes or more. If the melting time is too short, the glass raw materials will not melt sufficiently, making it difficult to obtain a precursor glass material with a uniform composition. If the melting time is too long, the components of the melting container will easily dissolve into the molten glass.

[0033] In the precursor glass material production process, it is preferable to produce the precursor glass material by melting the glass raw material using a molten container. The molten container is preferably constructed with a surface in contact with the molten glass made of quartz, platinum, or a platinum alloy. For example, it is preferable to use a quartz crucible, a platinum crucible, a platinum-rhodium crucible, a reinforced platinum crucible, or a molten furnace lined with platinum or a platinum alloy as the molten container. Alternatively, the precursor glass material may be produced using a so-called containerless levitation method without a molten container.

[0034] In the precursor glass material manufacturing process, the molten atmosphere is preferably an atmospheric atmosphere, a vacuum atmosphere, an inert atmosphere, or a reducing atmosphere, with atmospheric atmosphere being more preferable. This makes it easier to reduce manufacturing costs. Furthermore, the atmosphere used when cooling and solidifying the molten glass is preferably an atmospheric atmosphere from the viewpoint of facilitating manufacturing.

[0035] Precursor glass material can be obtained by solidifying molten glass using a desired cooling method. The cooling method is not particularly limited, but for example, water cooling or roller rapid cooling can be used. These methods can yield fragmentary or flake-shaped precursor glass material. Using precursor glass material in these shapes makes it easier to melt the glass material in the melting process.

[0036] <Glass composition> The present invention's method for manufacturing glass materials allows for the suitable production of paramagnetic glass materials. For example, a Tb2O3-based glass material containing, in mol% terms, 10% to 90% Tb2O3, 51% to 89% B2O3 + Al2O3 + SiO2 + P2O, 0.01 ppm to 100 ppm FeO + Fe2O3, and an additional 0.001% to 1% CeO2 (external weight) can be suitably produced. Glass materials satisfying the above composition tend to exhibit high light transmittance in the visible to near-infrared wavelength range.

[0037] The content of each component is described below. The content of FeO + Fe2O3 is as described above and is omitted here. The following glass composition is a preferred composition for the glass material produced by the present invention, but it is preferable that the precursor glass material also has a similar composition except for CeO2. Specifically, the precursor glass material preferably contains, for example, 10% to 90% Tb2O3, 51% to 89% B2O3 + Al2O3 + SiO2 + P2O, and 0.01 ppm to 100 ppm FeO + Fe2O3 in mol%.

[0038] Tb2O3 is a component that increases the absolute value of Verde's constant and enhances the Faraday effect. The Tb2O3 content is preferably 10%~90%, 15%~49%, 16%~46%, 18%~45%, 20%~44%, 21%~43%, 22%~41%, over 25%~41%, and particularly 26%~40%. In particular, if you want to increase Verde's constant, the Tb2O3 content is preferably 52%~80%, 53%~75%, 54%~71%, 55%~69%, 56%~67%, 57%~65%, and particularly 58%~64%. If the Tb2O3 content is too low, the above effect will be difficult to obtain. If the Tb2O3 content is too high, vitrification will be difficult and devitrification will be more likely during crucible melting. In addition, the light transmittance of the glass material will tend to decrease. Note that Tb exists in glass in trivalent and tetravalent states, but in this invention, all of these are represented as Tb2O3.

[0039] Tb for all Tb 3+ The proportion is preferably 55% or more, 60% or more, 70% or more, 80% or more, and especially 90% or more in mole percent. This allows Tb to be relative to total Tb. 4+ This can reduce the proportion of Tb. 4+ It has absorption in the wavelength range of 300 nm to 1100 nm and tends to reduce the light transmittance of glass materials. Therefore, Tb relative to total Tb 3+ By setting the ratio to the above value, the absorption of laser light in the visible to near-infrared wavelength range is suppressed, making it easier to suppress the heat generation of the glass material. Therefore, the thermal lensing effect is more easily suppressed.

[0040] CeO2 is an ingredient that functions as an oxidizing agent. The CeO2 content, when measured by external weight, is preferably 0.001% to 1%, with more preferably 0.01% to 0.9%, 0.02% to 0.8%, 0.04% to 0.7%, 0.04% to 0.5%, and particularly preferably 0.04% to 0.4%. If the amount of CeO2 added is too low, the Fe contained in the glass will... 2+ Fe 3+ The oxidizing effect is reduced. If too much CeO2 is added, the light transmittance of the glass material tends to decrease.

[0041] B2O3, Al2O3, SiO2, and P2O5 form the glass skeleton, expanding the vitrification range and stabilizing vitrification. The content of B2O3+Al2O3+SiO2+P2O5 (total amount of B2O3, Al2O3, SiO2, and P2O5) is 1% to 89%, with 1% to 86%, 6% to 85%, 11% to 83%, 16% to 81%, 21% to 79%, 26% to 77%, 31% to 75%, 36% to 74%, 41% to 74%, 46% to 74%, 50% to 74%, 51% to 74%, 55% to 74%, and especially 60% to 74%. If the content of B2O3+Al2O3+SiO2+P2O5 is too low, vitrification becomes difficult. If the content of B2O3 + Al2O3 + SiO2 + P2O5 is too high, it becomes difficult to obtain a sufficient Faraday effect. The preferred range for each component is as follows:

[0042] The B2O3 content is preferably 0%-89%, 0%-88%, 0%-87%, 0%-85%, 0%-75%, 0%-70%, 0%-66%, 0%-56%, 0%-51%, 1%-44%, 1%-40%, 1%-40%, 2%-40%, 4%-40%, 5%-40%, 10%-40%, over 12%-40%, and particularly preferably 13%-40%.

[0043] The Al2O3 content is preferably 0%-89%, 0%-88%, 0%-87%, 0%-85%, 0%-75%, 0%-70%, 0%-66%, 0%-56%, 0%-51%, 1%-44%, 1%-40%, 1%-30%, and particularly preferably 1%-20%.

[0044] The SiO2 content is preferably 0%-89%, 0%-88%, 0%-87%, 0%-85%, 0%-75%, 0%-70%, 0%-66%, 0%-56%, 0%-51%, 0%-50%, 0%-49%, 0%-40%, 1%-40%, 5%-40%, and particularly preferably 10%-40%.

[0045] The P2O5 content is preferably 0%-89%, 0%-88%, 0%-87%, 0%-85%, 0%-75%, 0%-70%, 0%-66%, 0%-56%, 0%-51%, 0%-40%, 0%-30%, 0%-25%, 0%-20%, 0%-20%, 0%-15%, 0%-10%, 0%-5%, and particularly preferably 1%-5%.

[0046] In addition to the above components, the glass material of the present invention may contain the following components.

[0047] GeO2 forms the glass skeleton, expanding the vitrification range and stabilizing vitrification. The GeO2 content is preferably 0%-60%, 0%-55%, 0%-50%, 0%-45%, 0%-40%, and especially 0%-35%. Too much GeO2 makes it difficult to obtain a sufficient Faraday effect.

[0048] ZnO is a component that stabilizes vitrification. The ZnO content is preferably 0%-20%, 0%-15%, 0%-13%, 0%-10%, 0%-8%, and especially preferably 0%-5%. Too much ZnO makes devitrification more likely and makes it difficult to obtain a sufficient Faraday effect.

[0049] La2O3, Gd2O3, Y2O3, and Yb2O3 are components that stabilize vitrification. The preferred content of La2O3, Gd2O3, Y2O3, and Yb2O3 is 10% or less, 7% or less, 5% or less, 4% or less, 2% or less, and especially 1% or less, respectively. If the content of these components is too high, vitrification becomes more difficult. There is no particular lower limit to the content of La2O3, Gd2O3, Y2O3, and Yb2O3, but for example, each is 0.1% or more.

[0050] Dy2O3, Eu2O3, Pr2O3, and Sm2O3 have light absorption in the visible to near-infrared wavelength range. Therefore, the content of Dy2O3, Eu2O3, Pr2O3, and Sm2O3 is preferably less than 5%, 3% or less, 2% or less, 1% or less, 500 ppm or less, and especially preferably 100 ppm or less, respectively. If the content of these components is too high, the light transmittance in the visible to near-infrared wavelength range tends to decrease. Note that Dy, Eu, Pr, and Sm exist in the glass in divalent, trivalent, and tetravalent states, but in this invention, they are represented as Dy2O3, Eu2O3, Pr2O3, and Sm2O3, respectively. There is no particular lower limit to the content of Dy2O3, Eu2O3, Pr2O3, and Sm2O3, but for example, each is 0.001 ppm or more.

[0051] MgO, CaO, SrO, and BaO are components that stabilize vitrification and enhance chemical durability. The preferred content of MgO, CaO, SrO, and BaO is 0% to 10%, particularly 0% to 5%. If the content of these components is too high, it becomes difficult to obtain a sufficient Faraday effect.

[0052] Ga2O3 is a component that stabilizes vitrification and easily broadens the vitrification range. The Ga2O3 content is preferably 0% to 6%, 0% to 5%, 0% to 4%, and especially 0% to 2%. Too much Ga2O3 content makes devitrification more likely and makes it difficult to obtain a sufficient Faraday effect.

[0053] Fluorine is a component that enhances glass-forming ability and easily broadens the vitrification range. The fluorine content (F2 equivalent) is preferably 0% to 10%, 0% to 7%, 0% to 5%, 0% to 3%, 0% to 2%, and particularly preferably 0% to 1%. If the fluorine content is too high, the component may volatilize during melting, adversely affecting vitrification. It may also increase the likelihood of striation formation.

[0054] The glass material preferably has a light transmittance of 70% or more, 75% or more, 80% or more, and particularly 83% or more at a wavelength of 1064 nm. Furthermore, at a wavelength of 633 nm, it is preferable that the light transmittance is 60% or more, 65% or more, 70% or more, and particularly 75% or more. Moreover, at a wavelength of 532 nm, it is preferable that the light transmittance is 30% or more, 50% or more, 60% or more, and particularly 70% or more. Note that the above light transmittance values ​​are for when the thickness of the glass material is 1 mm.

[0055] The glass material manufactured according to the present invention has the above-described structure, thereby suppressing the thermal lensing effect. Therefore, the glass material manufactured according to the present invention can be suitably used in magneto-optical elements (e.g., Faraday rotors) that constitute magnetic devices such as optical isolators, optical circulators, and magnetic sensors. [Examples]

[0056] The present invention will be described below based on examples, but the present invention is not limited to these examples.

[0057] Tables 1-3 show Examples 1-14 and Comparative Example 15 of the present invention.

[0058] [Table 1]

[0059] [Table 2]

[0060] [Table 3]

[0061] Examples 1-14 were prepared as follows. First, the raw materials were mixed to obtain 300g of glass material, resulting in the composition of the precursor glass material shown in Tables 1-3. The glass material was placed in a quartz crucible and melted at 1350°C for 1 hour in an air atmosphere. After melting, the molten glass was cooled with water in an air atmosphere and solidified to obtain the precursor glass material. At this time, the precursor glass material was in the form of fragments.

[0062] Next, CeO2 was added to the obtained precursor glass material in the proportions shown in Tables 1-3, based on external molar percentage, and mixed. Then, 100g of the CeO2-added precursor glass material was placed in a platinum crucible and melted under the conditions described in Tables 1-3. After melting, the molten glass was poured onto a carbon plate in an air atmosphere to obtain glass material. The obtained glass material was annealed in an air atmosphere at 770°C for 1 hour.

[0063] Comparative Example 15 was obtained by obtaining a precursor glass material using the same procedure as in Examples 1 to 14, and then melting the glass material in an air atmosphere without adding CeO2.

[0064] For the obtained glass material, the Verde constant, light transmittance, and Tb relative to total Tb were measured. 3+ The proportions of each were measured. The results are shown in Tables 1-3.

[0065] The Verde constant was measured using the rotational analyzer method. Specifically, the obtained glass material was polished to a thickness of 1 mm, and the Faraday rotation angle was measured in a magnetic field of 10 kOe in the wavelength range of 400 nm to 1100 nm, and the Verde constant at a wavelength of 532 nm was calculated.

[0066] Light transmittance was measured using a spectrophotometer (V-670, JASCO Corporation). Specifically, the obtained glass material was polished to a thickness of 1 mm, and the light transmittance at a wavelength of 532 nm was read from the light transmittance curve. Note that the light transmittance is the external transmittance, including reflection.

[0067] Tb for all Tb 3+The proportion was measured using X-ray absorption fine structure analysis (XAFS). Specifically, the spectrum of the X-ray absorption edge structure region (XANES) was obtained, and the proportion of Tb relative to total Tb was calculated from the shift amount of the peak position of each Tb ion. 3+ The percentage was calculated.

[0068] As shown in Tables 1-3, the glass materials of Examples 1-14 had an absolute value of Verde constant of 0.531-0.822 min / Oe·cm at a wavelength of 532 nm. Furthermore, the light transmittance of all of them was 70% or higher at 532 nm, indicating good light transmittance. On the other hand, as shown in Table 3, Comparative Example 15 had a low light transmittance of 55% at 532 nm. [Industrial applicability]

[0069] Glass materials produced by the manufacturing method of the present invention can be suitably used as magneto-optical elements (for example, Faraday rotors) that constitute magnetic devices such as optical isolators, optical circulators, and magnetic sensors.

Claims

1. A method for manufacturing glass materials, The aforementioned glass material is a paramagnetic glass material. FeO and / or Fe ２ O ３ Glass raw materials containing CeO ２ The process of adding In a vacuum atmosphere, an inert atmosphere, or a reducing atmosphere, CeO ２ The process includes a melting step for melting the glass raw material to which the additive has been added, The FeO + Fe₂O₃ content in the glass raw material is 0.01 ppm to 100 ppm. The amount of CeO₂ added is 0.001% to 1% in terms of external molar percentage. A method for manufacturing glass materials.

2. The paramagnetic glass material is Tb ２ O ３ A method for manufacturing a glass material according to claim 1, wherein the glass material is a glass-based material.

3. The above-mentioned Tb ２ O ３ -based glass material contains, in mol%, Tb ２ O ３ 10% to 80%, B ２ O ３ +Al ２ O ３ +SiO ２ +P ２ O ５ 16% to 89%, FeO + Fe ２ O ３ 0.01 ppm to 100 ppm, and further contains, by external division, CeO ２ 0.001% to 1%. The method for manufacturing the glass material according to claim 2.

4. In the melting process, Fe ２＋ Fe ３＋ Oxidized to Tb ４＋ Tb ３＋ A method for manufacturing a glass material according to claim 2 or 3, which reduces to

5. The method for manufacturing a glass material according to any one of Claims 2 to 4, wherein the ratio of Tb³⁺ to the total Tb of the glass material is 55% or more in mol%.

6. The method for manufacturing a glass material according to any one of claims 1 to 5, wherein the glass raw material is a precursor glass.

7. The method for producing a glass material according to claim 6, further comprising the step of melting glass raw materials other than CeO2 to prepare the precursor glass material.

8. A method for manufacturing a glass material according to any one of claims 1 to 7, wherein the glass material substantially does not contain Sb₂O₃ and As₂O₃.

9. The method for manufacturing a glass material according to any one of claims 1 to 8, wherein the light transmittance of the glass material at a wavelength of 532 nm is 70% or more.

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