Abstract: An alkali-free glass substrate contains, as represented by mass % based on oxides: 54% to 68% of SiO2; 10% to 25% of Al2O3; 0.1% to 5.5% of B2O3; and 8% to 26% of MgO+CaO+SrO+BaO. The alkali-free glass substrate has ?-OH of 0.15 mm?1 to 0.35 mm?1, and a Cl content of 0.15 to 0.3 mass %. A bubble growth index I of the alkali-free glass substrate given by the following formula is 320 or more: I=590.5×[?-OH]+874.1×[Cl]?5.7×[B2O3]?33.3. In the formula, [?-OH] is ?-OH of the alkali-free glass substrate in mm?1, [Cl] is the Cl content of the alkali-free glass substrate in mass %, and [B2O3] is a B2O3 content of the alkali-free glass substrate in mass %.

Abstract: An alkali-free glass substrate contains, as represented by mass % based on oxides: 54% to 66% of SiO2; 10% to 23% of Al2O3; 6% to 12% of B2O3; and 8% to 26% of MgO+CaO+SrO+BaO. The alkali-free glass substrate has ?-OH of 0.15 mm?1 to 0.5 mm?1, and a Cl content of 0.1 to 0.35 mass %. A bubble growth index I of the alkali-free glass substrate given by the following formula is 280 or more: I=590.5×[?-OH]+874.1×[Cl]?5.7×[B2O3]?33.3. In the formula, [?-OH] is ?-OH of the alkali-free glass substrate in mm?1, [Cl] is the Cl content of the alkali-free glass substrate in mass %, and [B2O3] is a B2O3 content of the alkali-free glass substrate in mass %.

Abstract: The present invention relates to a float glass substrate including an alkali-free glass, the float glass substrate having a Cl content of from 0.10 to 0.50 mass %, containing substantially no SnO2, and having a Pt content of, by mass, from 0.001 to 0.30 ppm. The float glass substrate may have a Rh content of, by mass, from 0.001 to 0.50 ppm.

Abstract: To provide an alkali-free glass, of which the compaction is low, the strain point is high, and the ultraviolet transmittance is high, and which is easy to melt. An alkali-free glass, which comprises, as represented by mol % based on oxides, SiO2 from 65 to 75, Al2O3 from 9 to 15, B2O3 from 0 to 3, MgO from 0 to 12, CaO from 0 to 8, SrO from 0 to 6, and BaO from 0 to 5, wherein MgO+CaO+SrO+BaO is from 12 to 22, and 4.84[Fe2O3]+5.65[Na2O]+4.03[K2O]+4.55[SnO2] is at most 0.55, and of which the compaction is at most 80 ppm.

Abstract: The present invention relates to an alkali-free glass substrate in which when the alkali-free glass substrate is melted, and while holding a temperature at 1400° C., reduced in pressure from an atmospheric pressure to 33.33 kPa at a constant pressure reduction rate for 20 minutes and held at 33.33 kPa for 5 minutes, a diameter of a grown bubble is at least 3 times a diameter of an initial bubble. A bubble having a diameter of 0.1 to 0.3 mm contained in a molten glass at 1400° C. before starting pressure reduction is defined as the initial bubble. A bubble after held at 33.33 kPa for 5 minutes corresponding to the initial bubble is defined as a grown bubble.

Abstract: An alkali-free glass has a strain point of 650° C. or more, an average coefficient of thermal expansion at 50 to 350° C. of from 30×10?7 to 45×10?7/° C., and a temperature T2 at which a glass viscosity reaches 102 dPa·s of from 1,500 to 1,800° C. The alkali-free glass contains, as represented by mol % based on oxides, SiO2: from 62 to 70%, Al2O3: from 9 to 16% B2O3: from 0 to 12%, MgO: from 3 to 10%, CaO: from 4 to 12%, SrO: from 0 to 6%, and Fe2O3: from 0.001 to 0.04%, provided that MgO+CaO+SrO+BaO is from 12 to 25%. The alkali-free glass has a ?-OH value of from 0.35 to 0.85/mm.

Abstract: An alkali-free glass substrate contains, as represented by mass % based on oxides: 54% to 66% of SiO2; 10% to 23% of Al2O3; 6% to 12% of B2O3; and 8% to 26% of MgO+CaO+SrO+BaO. The alkali-free glass substrate has ?-OH of 0.15 mm?1 to 0.5 mm?1, and a Cl content of 0.1 to 0.35 mass %. A bubble growth index I of the alkali-free glass substrate given by the following formula is 280 or more: I=590.5×[?-OH]+874.1×[Cl]5.7×[B2O3]?33.3. In the formula, [?-OH] is ?-OH of the alkali-free glass substrate in mm?1, [Cl] is the Cl content of the alkali-free glass substrate in mass %, and [B2O3] is a B2O3 content of the alkali-free glass substrate in mass %.

Abstract: An alkali-free glass substrate contains, as represented by mass % based on oxides: 54% to 68% of SiO2; 10% to 25% of Al2O3; 0.1% to 5.5% of B2O3; and 8% to 26% of MgO+CaO+SrO+BaO. The alkali-free glass substrate has ?-OH of 0.15 mm?1 to 0.35 mm?1, and a Cl content of 0.15 to 0.3 mass %. A bubble growth index I of the alkali-free glass substrate given by the following formula is 320 or more: I=590.5×[?-OH]+874.1×[Cl]?5.7×[B2O3]?33.3. In the formula, [?-OH] is ?-OH of the alkali-free glass substrate in mm?1, [Cl] is the Cl content of the alkali-free glass substrate in mass %, and [B2O3] is a B2O3 content of the alkali-free glass substrate in mass %.

Abstract: The present invention relates to an alkali-free glass and a method for producing the same. More specifically, the present invention relates to an alkali-free glass suitable as a glass for substrates of various displays such as liquid crystal display, and a method for producing the same. According to the present invention, an alkali-free glass suitable as a glass for display substrates, in which inclusion of bubbles is greatly reduced by virtue of containing a refining agent and suppressing the stirring reboil, is obtained.

Abstract: The present invention relates to an alkali-free glass and a method for producing the same. More specifically, the present invention relates to an alkali-free glass suitable as a glass for substrates of various displays such as liquid crystal display, and a method for producing the same. According to the present invention, an alkali-free glass suitable as a glass for display substrates, in which inclusion of bubbles is greatly reduced by virtue of containing a refining agent and suppressing the stirring reboil, is obtained.

Abstract: To provide an alkali-free glass, of which the compaction is low, the strain point is high, and the ultraviolet transmittance is high, and which is easy to melt. An alkali-free glass, which comprises, as represented by mol % based on oxides, SiO2 from 65 to 75, Al2O3 from 9 to 15, B2O3 from 0 to 3, MgO from 0 to 12, CaO from 0 to 8, SrO from 0 to 6, and BaO from 0 to 5, wherein MgO+CaO+SrO+BaO is from 12 to 22, and 4.84[Fe2O3]+5.65[Na2O]+4.03[K2O]+4.55[SnO2] is at most 0.55, and of which the compaction is at most 80 ppm.

Abstract: The present invention relates to an alkali-free glass substrate in which when the alkali-free glass substrate is melted, and while holding a temperature at 1400° C., reduced in pressure from an atmospheric pressure to 33.33 kPa at a constant pressure reduction rate for 20 minutes and held at 33.33 kPa for 5 minutes, a diameter of a grown bubble is at least 3 times a diameter of an initial bubble. A bubble having a diameter of 0.1 to 0.3 mm contained in a molten glass at 1400° C. before starting pressure reduction is defined as the initial bubble. A bubble after held at 33.33 kPa for 5 minutes corresponding to the initial bubble is defined as a grown bubble.

Abstract: To provide a glass for a display substrate which has solved yellowing problems. A glass plate for a display substrate, which contains at least one member selected from the group consisting of Ti, Mn, Zn, Y, Nb, La, Ce and W in an amount of from 0.1 to 10 mass % as calculated as oxides.

Abstract: A crystallized glass for an optical filter substrate, which has an average linear expansion coefficient ?L of from 95×10?7/° C. to 130×10?7/° C. at from ?30° C. to 70° C. and which has a crystal or the like of Na4-xKxAl4Si4O16 (1<x?4) precipitated therein. Further, a crystallized glass for an optical filter substrate, which comprises from 35 to 60% of SiO2, from 10 to 30% of Al2O3, from 1 to 15% of TiO2+ZrO2, from 4 to 20% of Na2O, from 4 to 20% of K2O, from 0.1 to 10% of CaO+SrO+Bao, from 0 to 10% of MgO, etc., and which has ?L of from 95×10?7/° C. to 130×10?7/° C. and which has a crystal or solid solution precipitated therein.

Abstract: A crystallized glass for an optical filter substrate, which has an average linear expansion coefficient &agr;L of from 95×10−7/° C. to 130×10−7/° C. at from −30° C. to 70° C. and which has a crystal or the like of Na4-xKxAl4Si4O16 (1<x≦4) precipitated therein. Further, a crystallized glass for an optical filter substrate, which comprises from 35 to 60% of SiO2, from 10 to 30% of Al2O3, from 1 to 15% of TiO2+ZrO2, from 4 to 20% of Na2O, from 4 to 20% of K20, from 0.1 to 10% of CaO+SrO+Bao, from 0 to 10% of MgO, etc., and which has &agr;L of from 95×10−7/° C. to 130×10−7/° C. and which has a crystal or solid solution precipitated therein.