JP2003048747A - Easily recyclable colored glass, method for manufacturing the same and method for recycling the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a glass which can be recycled without separating from a colorless glass, to provide a method for manufacturing the glass and a method for recycling glass. SOLUTION: The colored glass contains Mn by 0.02 to 1 mol% with respect to the structural components of the glass and shows 0.1 to 1 absorbance at 530 to 560 nm wavelength for 1 mm thickness. The method for manufacturing the above glass and the method for recycling the glass are also presented.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to colored glass or colorless glass, a method for producing the same, and a method for recycling glass.

[0002]

2. Description of the Related Art Currently, the glass currently on the market is mainly colorless glass and brown glass, and other colored glasses have not been recycled. This is because the colored glass needs to be separated from the colorless glass at the time of recycling, which complicates the recycling process and increases the cost.

In order that colored glass can be recycled without being separated from colorless glass, development of colored glass satisfying the following points is required.・ When it is used as a colored glass, the coloring is stable under the normal use environment. ・ The coloring disappears when it is remelted for recycling. ・ The recycled colorless glass does not color in direct sunlight. A colored glass having such characteristics has not yet been developed.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the problems of the prior art, and is mainly glass that can be recycled without separating it from colorless glass, a method for producing the same, and a method for recycling glass. The purpose is to provide.

[0005]

As a result of earnest research, the inventor has found that a glass having a specific composition can achieve the above object, and has completed the present invention.

That is, the present invention relates to the following glass, its manufacturing method and glass recycling method. 1. When Mn is included in the glass composition in an amount of 0.02 to 1 mol% and the thickness is 1 mm, the absorbance at 530 to 560 nm is 0.1 to 1
Is a colored glass. 2. It contains 0.02 to 1 mol% of Mn with respect to the glass components, and further contains at least one electron scavenger selected from the group consisting of Fe, Sn, Sb, and As. When Fe is contained, the content is Mn-containing. The molar ratio to the amount is 100-200%, Sn,
When Sb and As are included, the content of each element is 50 to 200% in molar ratio with respect to the Mn content, and the absorbance at 530 to 560 nm when the thickness is 1 mm is 0.1 to 1
Is a colored glass. 3. The colored glass as described in 1 or 2 above, which is decolored by heating at 450 to 600 ° C. 4. A method for producing a colored glass, which comprises irradiating a colorless glass containing Mn in an amount of 0.02 to 1 mol% with respect to glass constituents with X-rays or gamma rays and heat-treating at 300 ° C or lower. 5. It contains 0.02 to 1 mol% of Mn with respect to the glass components, and further contains at least one electron scavenger selected from the group consisting of Fe, Sn, Sb and As. When Fe is contained, the content is Mn-containing. The molar ratio to the amount is 100-200%, Sn,
In the case of containing Sb and As, for each element, a colorless glass whose content is 50 to 200% in molar ratio with respect to the Mn content is irradiated with X-rays or gamma rays and heat-treated at 300 ° C or less. A method for producing a colored glass, which is characterized. 6. 450 ℃ the colored glass according to any one of the above 1-3
A method for recycling glass, including the step of decoloring by heat treatment as described above. 7. A colorless glass containing 0.02 to 1 mol% of Mn with respect to the glass components. 8. It contains 0.02 to 1 mol% of Mn with respect to the glass components, and further contains at least one electron scavenger selected from the group consisting of Fe, Sn, Sb and As. When Fe is contained, the content is Mn-containing. The molar ratio to the amount is 100-200%, Sn,
When Sb and As are contained, the content of each element is a colorless glass whose molar ratio is 50 to 200% with respect to the Mn content. 9. A method for producing colorless glass, which comprises a step of melting a glass raw material containing 0.02 to 1 mol% of a glass constituent, a reducing agent and Mn with respect to the glass constituent. 10. The method includes a step of melting a glass raw material containing a glass component, Mn and at least one electron scavenger selected from the group consisting of Fe, Sn, Sb and As, and the content of Mn is
0.02 to 1 mol% with respect to the glass components, when containing Fe, the content is 100 to 200 in molar ratio to the Mn content.
%, And when Sn, Sb and As are included, the content of each element is 50 to 50 in molar ratio with respect to the Mn content.
A method for producing 200% colorless glass.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention contains Mn in an amount of about 0.02 to 1 mol% with respect to glass constituents and has a thickness of 1 mm.
The present invention relates to a colored glass whose absorbance at 0 to 560 nm is about 0.1 to 1. The colored glass of the present invention includes not only glass that is entirely colored, but also glass that is at least partially colored.

The content of Mn in the colored glass of the present invention is usually about 0.02 to 1 mol%, preferably 0.04 to 0.
It is about 2 mol%, and more preferably about 0.05 to 0.1 mol%.

The colored glass of the present invention further comprises Fe, Sn, Sb.
And at least one electron scavenger selected from the group consisting of As. The content of Fe is usually about 100 to 200%, preferably 10 by molar ratio with respect to the content of Mn.
It is about 0 to 150%. The content of Sn, Sb and As is usually a molar ratio with respect to the Mn content for each element.
It is about 50 to 200%, preferably about 50 to 100%.

The glass after coloring has a thickness of 5 mm when the thickness is 1 mm.
The absorbance at 30 to 560 nm is usually about 0.1 to 1, preferably about 0.3 to 1. The absorbance at 400 nm of the colored glass of the present invention is usually about one third of the absorbance at 550 nm.
Or less, preferably about 1/4 or less. The colored glass of the present invention has a low absorbance at 400 nm and produces a vivid color.

The glass component (basic composition) of the glass of the present invention is not particularly limited. For example, one-component quartz glass, multi-component silicate glass (e.g. Na ₂ O-SiO ₂ system, Na
₂ O-CaO-SiO ₂ system, Na ₂ O-CaO-SiO ₂ -Al ₂ O ₃ system) and the like silicate glass can be exemplified. Among these, multi-component silicate glass is preferable.

In the glass of the present invention, SiO ₂ as a glass constituent component is usually about 60 to 80 mass%, preferably 65 to 75 mass%.
s%, particularly preferably 70 to 74 mass%. Similarly, the glass of the present invention, as a glass constituent, Ca
O is usually about 5 to 20 mass%, preferably about 7 to 12 mass%,
Particularly preferably, it is contained in an amount of about 10 to 11 mass%, Na ₂ O is usually contained in an amount of about 10 to 25 mass%, preferably about 12 to 18 mass%, and particularly preferably about 13 to 14 mass%.

If necessary, the glass of the present invention may contain Al ₂ O ₃ , K ₂ O, MgO, BaO, SO ₃ , B ₂ O ₃ and the like. The content of Al ₂ O ₃ is usually about 0 to 5 mass%, preferably about 1 to ₃ mass%, and particularly preferably about 1.5 to 2 mass%. The content of K ₂ O is usually about 0 to 3 mass%, preferably about 0 to ₂ mass%. The content of MgO is usually 0-3ma
It is about ss%, preferably about 0 to 2 mass%. The content of BaO is usually about 0 to 5 mass%, preferably about 0 to 1 mass%. The content of SO ₃ is usually about 0 to 1 mass%, preferably about 0 to 0.5 mass%. B ₂ O ₃ content is usually 0
It is about 15 to 15 mass%, preferably about 0 to 0.1 mass%.

The colored glass of the present invention is obtained by irradiating a colorless glass containing Mn in an amount of 0.02 to 1 mol% with respect to the glass constituents with X-rays or gamma rays and heat-treating at about 300 ° C. or below; On the other hand, it contains about 0.02 to 1 mol% and further contains at least one kind of electron scavenger selected from the group consisting of Fe, Sn, Sb and As. When Fe is contained, the content thereof is mol relative to the Mn content. The ratio is about 100 to 200%, and when Sn, Sb and As are included, the content of each element is 50 to 200% in terms of molar ratio with respect to the Mn content.
Irradiate X-rays or gamma rays on colorless glass,
It can be manufactured by a method of heat treatment at about 300 ° C. or lower.

The acceleration voltage of X-rays is not particularly limited,
Usually, it is about 10 to 400 kV, preferably about 30 to 400 kV, more preferably about 50 to 300 kV. The output of X-rays can be appropriately set according to the amount of Mn contained in the glass. X-ray output is usually about 0.1 to 50 kW, preferably 1 to 5
It is about 0 kW, more preferably about 2 to 30 kW. The irradiation time can be appropriately set according to the amount of Mn contained in the glass, the output of X-rays, etc., but is usually about 0.1 to 6 minutes, preferably about 0.2 to 30 minutes, more preferably about 0.3 to 10 minutes. Is. The larger the X-ray output, the shorter the irradiation time and the more the coloring.

The energy of gamma rays for irradiation is not particularly limited, but is usually about 0.01 to 5 MeV, preferably 1 to 2 MeV.
It is about V. The irradiation intensity of gamma rays is not particularly limited, but is usually about 1 to 1000 C / kg · h, preferably 100 to 1000.
It is about C / kg · h. Irradiation time is not particularly limited, but is usually about 0.1 to 5 hours, preferably about 0.1 to 1 hour.

The heating conditions for coloring after irradiation with X-rays or gamma rays are not particularly limited. The heating temperature is usually about 300 ° C or lower, preferably about 120 ° C to 300 ° C, more preferably about 150 ° C to 250 ° C. The heating time is usually about 5 minutes to 120 minutes, preferably about 15 minutes to 60 minutes, more preferably about 20 minutes to 40 minutes.

The colorless glass before being irradiated with X-rays or gamma rays is, for example, each glass raw material (glass constituent, Mn and, if necessary, an electron scavenger) prepared so as to have a desired composition and carbon and the like. It can be produced by a method of melting a reducing agent. The reducing agent is not limited to carbon, and may be any substance that burns at the melting temperature and does not leave a solid component. As a specific example of the reducing agent, starch
Carbohydrates such as (starch); hydrocarbons such as paraffin; polyethylene terephthalate, polyethylene, polypropylene, polyimide, polyvinyl, polymethylmethacrylate, polymethacrylate, polystyrene, polyvinyl butyral, polyvinyl acetal, polycarbonate, polyethylene glycol, acryl nitryl butadiene styrene. Examples thereof include organic compounds such as polymer compounds such as polyacetal, polyester, polyvinyl chloride, acrylonitrile styrene, and polyamide. As the polymer compound, polyethylene terephthalate, polyethylene, polypropylene, polystyrene, polyester, acrylonitrile butadiene styrene, polycarbonate, polymethyl methacrylate, polyvinyl butyral and the like are preferable. Waste materials such as waste plastics can also be used as the polymer compound. As the reducing agent, one type may be used alone, or two or more types may be used in combination.

The melting conditions can be appropriately set according to the glass composition and the like. The melting temperature is usually 1300 ° C-16
The temperature is about 00 ° C, preferably about 1400 ° C to 1500 ° C. The melting time is not particularly limited as long as it is a time sufficient to uniformly melt each raw material, but is usually about 1 to 24 hours, preferably about 5 to 20 hours.

The amount of the reducing agent such as carbon added is not particularly limited, but is usually about 50% or more, preferably about 60 to 100% in terms of molar ratio with Mn. The reducing agent has a function of reducing high-valence Mn such as Mn ³⁺ and Mn ⁴⁺ to Mn ²⁺ . Carbon is burned when each glass raw material is melted to form colorless glass, and thus the obtained glass does not contain carbon.

Like the reducing agent, the electron scavenger has a function of reducing Mn having a high valence to Mn ²⁺ .
At least one selected from the group consisting of Sn, Sb and As
When a kind of electron scavenger is contained, the amount of the reducing agent such as carbon added can be reduced according to the content of the electron scavenger. In the case of Fe, about 50% of the added amount (molar ratio), S
In the case of n, Sb and As, the amount of carbon added can be reduced by the same amount as the amount added. Therefore, when the electron scavenger is sufficiently contained, a colorless glass can be obtained without adding carbon. However, when the content of Fe is too large, there is a possibility that coloring from yellow to yellowish green may already occur at the stage of glass before coloring by irradiation.

In order to mix Mn into glass, MnO ₂ or the like may be used as a glass raw material. In order to mix Fe into glass, as a glass raw material, for example, Fe
₂ O ₃ or the like may be used. In order to add Sn to glass, for example, SnO or the like may be used as a glass raw material. In order to add Sb to glass, for example, Sb ₂ O ₃ may be used as a glass raw material. To incorporate As into glass, as a glass raw material, for example, As ₂ O ₃
Etc. may be used. Further, if necessary, Al ₂ O ₃ , K ₂ O,
_{MgO, BaO, SO 3, B} 2 O 3 or the like may be used as a glass raw material.

The glass of the present invention can be prepared by using a known method.
It can be molded into a desired shape before coloring.

The colored glass of the present invention can be decolored by heat treatment. The colored glass of the present invention can be decolored by remelting, but it can also be decolored by heating at a relatively low temperature near the glass transition point. The heat treatment temperature for decoloring is usually about 450 ° C or higher. When re-melting, preferably about 1100 ~ 1600 ℃, more preferably 1400 ~ 1500
It may be heated to about ℃. The heating time for remelting is usually about 1 to 24 hours, preferably about 2 to 12 hours. In the case of erasing the color while maintaining the shape of the glass, it is preferable to heat to about 450 to 600 ° C, more preferably about 500 to 550 ° C. When the color is erased while maintaining the shape, the heating time is usually about 5 minutes to 120 minutes, preferably about 15 minutes to 60 minutes, more preferably about 20 minutes to 40 minutes.

An electron scavenger such as Fe, Sn, Sb, As acts as a reducing agent during the production of colorless glass to reduce manganese to divalent, and absorbs electrons emitted during X-ray or gamma-ray irradiation. Helps to oxidize manganese, that is, to develop color. During heat treatment at high temperature, the electron scavenger releases electrons absorbed during light irradiation, so that manganese is reduced again to become colorless.

The colored glass of the present invention can be recycled without being separated from colorless glass. It is also possible to recycle using only the glass of the present invention. Since the colored glass of the present invention can be decolored and colored by heating at a temperature near the glass transition point, for example, decoloring while maintaining the shape of the glass, and recoloring while maintaining the shape. Thus, the glass can be recycled.

[0027]

The glass of the present invention can be recycled without being separated from colorless glass.

The colored glass of the present invention is stably colored (difficult to fade) under normal use environment.

The colored glass of the present invention is decolored when remelted for recycling. Further, since the colored glass of the present invention is decolored by heating at a relatively low temperature near the glass transition point, it can be decolorized or recycled while maintaining the shape of the glass.

[0030]

EXAMPLES Examples of the present invention will be given below together with comparative examples.
The present invention will be described more specifically. The present invention is not limited to the examples below.

Example 1 Glass having a composition similar to that of bottle glass (74 mol% SiO ₂ · 16 m
ol% Na ₂ O.10mol% CaO) was used as the glass component. 0.1 mol% MnO ₂ and 0.1 mo
The raw material was prepared to contain 1% SnO, and the mixture was melted at 1400 ° C for 3 hours until uniform. The obtained glass was molded into a plate-like glass having a thickness of 2 mm, and slowly cooled and polished to obtain a colorless plate-like glass. The absorption spectrum of this colorless glass is shown as (a) Original in FIG.

X-rays with Rh as a radiation source were applied to this glass at 50 kV and 5
Irradiate with 0 mA for 2 minutes. The obtained glass had a dark brown color. Figure 1 shows the absorption spectrum of glass after X-ray irradiation.
Shown as (b) X-ray emitted.

Further, this glass was heat-treated at 200 ° C. for 1 hour to obtain a vivid blue-violet glass. The absorption spectrum of this blue-violet glass is shown in FIG. 1 as (c) Heat treated at 200 ° C.

When this glass was left at room temperature in a bright place for one month, almost no color change was observed. Figure 1 shows the absorption spectrum of the glass after left for 1 month (d) One mo
Shown as nthafter c.

When this glass was heated at 600 ° C. for 1 hour, a colorless glass was obtained. The absorption spectrum of this colorless glass is shown in FIG. 1 as (e) Heat treated at 600 ° C. This absorption spectrum was almost the same as that of the colorless glass before coloring.

Example 2 A transparent plate glass having a thickness of 2 mm was prepared in the same manner as in Example 1 except that 0.05 mol% Fe ₂ O ₃ was used instead of SnO as an electron scavenger. The absorption spectrum of this colorless glass is shown as (a) Original in FIG.

X-rays with Rh as a radiation source were applied to this glass at 50 kV, 5
Irradiate with 0 mA for 2-30 minutes. The obtained glass had a dark brown color. The absorption spectrum of the glass after X-ray irradiation is shown as (b) X-ray irradiated in FIG.

Further, by subjecting this glass to a heat treatment at 200 ° C. for 1 hour, a vivid blue-violet glass was obtained. The absorption spectrum of this blue-violet glass is shown in FIG. 2 as (c) Heat treated at 200 ° C.

When this glass was heated at 500 ° C. for 1 hour, a colorless glass was obtained. The absorption spectrum of this colorless glass is shown in FIG. 2 as (d) Heat treated at 500 ° C. This absorption spectrum was almost the same as that of the colorless glass before coloring.

Further, when the X-ray irradiation, the heat treatment for coloring and the heat treatment for decoloring were repeated under the same conditions, the coloring and decoloring were performed with good reproducibility. The absorption spectra at each stage are shown as (e), (f) and (g) in FIG.

Comparative Example 1 An ultraviolet lamp (wavelength: 185) was applied to glass having the same composition as the colorless glass used in Example 2 before irradiation with X-rays.
Irradiation with 210 μW / cm ² was performed at ˜254 nm, output 90 W). After irradiation for 12 hours, it was colored only in a very pale bluish purple.

Example 3 A transparent plate having a thickness of 2 mm was prepared in the same manner as in Example 1 except that 0.1 mol% of MnO ₂ and 0.06 mol% of carbon powder were used as a reducing agent and no electron scavenger was used. The shaped glass was created. The absorption spectrum of this colorless glass is shown in Figure 3 (a) Original.
Indicated as.

X-rays with Rh as a radiation source were applied to this glass at 50 kV and 5
Irradiate with 0 mA for 30 minutes. The obtained glass had a dark brown color. Figure 3 shows the absorption spectrum of glass after X-ray irradiation.
Shown as (b) X-ray emitted.

Further, by subjecting this glass to a heat treatment at 200 ° C. for 1 hour, a vivid blue-violet glass was obtained. The absorption spectrum of this blue-violet glass is shown in FIG. 3 as (c) Heat treated at 200 ° C.

The glass became colorless when heated at 500 ° C. for 1 hour.

Comparative Example 2 Glass having a composition similar to that of bottle glass (74 mol% SiO ₂ · 16 m
ol% Na ₂ O ・ 10mol% CaO) as a glass constituent,
A glass raw material was prepared so that 0.1 mol% of MnO ₂ was contained with respect to the glass constituents, and this was melted at 1400 ° C. for 3 hours until it became uniform. The obtained glass was shaped into a plate glass having a thickness of 2 mm, gradually cooled and polished. The obtained plate glass had a bright reddish purple color before being irradiated with electromagnetic waves. The absorption spectrum of the obtained glass is shown in FIG.

This glass did not disappear even when heated to 450 ° C. or higher.

[Brief description of drawings]

FIG. 1 shows the results of Example 1. That is, it shows the change in absorption spectrum due to X-ray irradiation and heat treatment in the glass containing MnO ₂ and SnO.

FIG. 2 shows the results of Example 2. That is, the change of the absorption spectrum by the X-ray irradiation and the heat treatment in the glass containing MnO ₂ and Fe ₂ O ₃ is shown.

FIG. 3 shows the results of Example 3. That is, the change of the absorption spectrum by the X-ray irradiation and the heat treatment in the MnO ₂ -containing glass reduced with C is shown.

FIG. 4 is an absorption spectrum of the glass obtained in Comparative Example 2.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C03C 23/00 B09B 3/00 ZAB (72) Inventor Masaru Yamashita 1-831 Midorigaoka, Ikeda-shi, Osaka Independent Administrative Agency National Institute of Advanced Industrial Science and Technology Kansai Center (72) Inventor Kohei Kakuno 1-831 Midorigaoka, Ikeda-shi, Osaka Independent Administrative Agency National Institute of Advanced Industrial Science and Technology (72) Inventor Tetsuo Yazawa Osaka 1-83-1 Midorigaoka, Ikeda-shi, Fukushima Independent administrative agency National Institute of Advanced Industrial Science and Technology Kansai Center (72) Inventor Tomoko Akai 1-8-31 Midorigaoka, Ikeda-shi, Osaka Prefectural Government In the center (72) Inventor Osamu Yato 1-2-25 Nagara Nishi, Kita-ku, Osaka City, Osaka Prefecture Within Osaka Seiko Glass Co., Ltd. (72) Inventor Yasushi Utagawa Osaka Prefectural City Kita-ku Kita-ku 1-2-25 Nagara Nishi Within Osaka Seiko Glass Co., Ltd. (72) Inventor Nobuyuki Itakura 1510 Oguchi-cho, Matsusaka-shi, Mie Central Glass Co., Ltd. Glass Research Laboratory F-term (reference) 4D004 AA18 AC04 BA10 CA22 CA29 CB50 CC20 DA03 DA06 DA10 4G059 AA01 AA04 AA18 AB09 AC08 4G062 AA01 BB03 BB05 CC04 DA06 DA07 DB01 DB02 DB03 DC01 DC02 DC03 DC04 DD01 DE01 DF01 FB01 FE01 FE01 FE01 FE01 FE01 FE01 FE01 FE01 FE01 FE01 FE01 FE02 EF01 EF01 EF01 EF01 FE02 FE01 FE02 FE01 FE01 FE01 FE02 FE01 FE02 FE01 FE02 FH01 FJ01 FK01 FL01 GA01 GB01 GB02 GB03 GC01 GD01 GE01 HH01 HH03 HH05 HH07 HH09 HH11 HH13 HH15 HH17 HH20 JJ01 JJ03 JJ04 JJ05 JJ07 JJ10 KK01 KK03 KK05 KK07 KK10 MM01 NN05

Claims (10)

[Claims] 1. Mn in an amount of 0.02 to 1 mol% with respect to glass constituents.
A colored glass which contains 0.1 to 1 at 530 to 560 nm and has a thickness of 1 mm. 2. Mn in an amount of 0.02 to 1 mol% based on the glass constituents.
And further includes at least one electron scavenger selected from the group consisting of Fe, Sn, Sb and As, and Fe.
When the content is 100 to 200% by mole ratio with respect to the Mn content, and Sn, Sb and As are included, the content of each element is 50 to 200 by mole ratio with respect to the Mn content. %, And the absorbance is 0.1 to 1 at 530 to 560 nm when the thickness is 1 mm. 3. The colored glass according to claim 1, which is decolored by heating at 450 to 600 ° C. 4. Mn in an amount of 0.02 to 1 mol% based on the glass constituents.
Irradiate the colorless glass containing X-rays or gamma rays to 300 ℃
A method for producing a colored glass, which comprises the following heat treatment. 5. Mn in an amount of 0.02 to 1 mol% based on the glass constituents.
And further includes at least one electron scavenger selected from the group consisting of Fe, Sn, Sb and As, and Fe.
When the content is 100 to 200% by mole ratio with respect to the Mn content, and Sn, Sb and As are included, the content of each element is 50 to 200 by mole ratio with respect to the Mn content. Irradiate colorless glass (%) with X-rays or gamma rays to 300 ℃
A method for producing a colored glass, which comprises the following heat treatment. 6. A method for recycling glass, which comprises a step of decoloring the colored glass according to any one of claims 1 to 3 by heat treatment at 450 ° C. or higher. 7. Mn in an amount of 0.02 to 1 mol% based on the glass constituents.
Including colorless glass. 8. Mn is 0.02 to 1 mol% with respect to the glass constituents.
And further includes at least one electron scavenger selected from the group consisting of Fe, Sn, Sb and As, and Fe.
When the content is 100 to 200% by mole ratio with respect to the Mn content, and Sn, Sb and As are included, the content of each element is 50 to 200 by mole ratio with respect to the Mn content. Colorless glass that is%. 9. A method for producing colorless glass, which comprises a step of melting a glass raw material containing 0.02 to 1 mol% of a glass constituent, a reducing agent and Mn with respect to the glass constituent. 10. A step of melting a glass raw material containing a glass component, Mn and at least one electron scavenger selected from the group consisting of Fe, Sn, Sb and As, wherein the content of Mn is glass. 0.02 to 1 mol% relative to the constituents,
When Fe is contained, its content is in molar ratio with respect to Mn content.
A method for producing a colorless glass in which the content of each element is 50 to 200% in a molar ratio with respect to the Mn content when the content is 100 to 200% and Sn, Sb and As are contained.