Abstract: The glass substrate having opposing flat two main surfaces includes a plurality of optically homogeneous glass pieces joined with one another, in which a junction surface between the joined glass pieces is perpendicular or substantially perpendicular with respect to the two main surfaces.

Abstract: [Problem] To provide glass having a colored layer. [Solution] Glass having a colored layer.

Abstract: Glass comprising a colored layer, wherein the glass contains one or more glass components selected from the group consisting of Sb ions, As ions, Sn ions, and Ce ions in an amount of 0.075 cation % or more.

Abstract: A ring-shaped glass spacer is configured to be arranged in contact with a magnetic disk in a hard disk drive apparatus. A surface resistivity of a surface of a glass material of the glass spacer at 22 (° C.) is lower than a surface resistivity of an inner portion of the glass material at 22 (° C.).

Abstract: A ring shaped glass spacer is configured to be arranged in contact with a magnetic disk in a hard disk drive apparatus. A surface resistivity of a surface of a glass material of the glass spacer at 22 (° C.) is lower than a surface resistivity of an inner portion of the glass material at 22 (° C.).

Abstract: A glass material of a glass spacer has a surface resistivity of 103 to 109 (?/sq) at 22 (° C.). The surface resistivity of a surface of the glass material of the glass spacer at 22 (° C.) is lower than the surface resistivity of an inner portion of the glass material at 22 (° C.). The glass spacer contains at least one oxide selected from the group consisting of TiO2, Nb2O5, WO3, and Bi2O3, as a glass component.

Abstract: A glass material of a glass spacer has a surface resistivity of 103 to 109 [?/sq] at 22 [° C.]. The surface resistivity of a surface of the glass material of the glass spacer at 22 [° C.] is lower than the surface resistivity of an inner portion of the glass material at 22 [° C.]. The glass spacer contains at least one oxide selected from the group consisting of TiO2, Nb2O5, WO3, and Bi2O3, as a glass component.

Abstract: A glass lens blank for polishing in which a thickness of a defect-containing layer is suppressed to a minimum and thus it is possible to shorten the processing time required for grinding and polishing the glass lens blank for polishing after press-molding, a method of manufacturing the same, and a method of manufacturing an optical lens. A glass lens blank for polishing of which at least a main surface is a press-molding surface, wherein a defect-containing layer formed on the main surface has a thickness of 50 ?m or less.

Abstract: To provide a fluorophosphates glass having a weather-resistant property and having an O2?/P5+ ratio even after production, which is set so that Cu2+ can be added with a quantity of such a degree suppressing an absorption of a visible light while absorbing a near-infrared light, and a method for producing the same, and a near-infrared light absorbing filter, wherein a molar ratio of a content of O2? with respect to a content of P5+ (O2?/P5+) in the fluorophosphates glass, is 3.2 or more and less than 3.4, and a molar ratio of a content of F? with respect to a total content of O2? and F? (F?/(O2?+F?)) in the fluorophosphates glass is 0.05 or more and 0.25 or less.

Abstract: A glass lens blank for polishing in which a thickness of a defect-containing layer is suppressed to a minimum and thus it is possible to shorten the processing time required for grinding and polishing the glass lens blank for polishing after press-molding, a method of manufacturing the same, and a method of manufacturing an optical lens. A glass lens blank for polishing of which at least a main surface is a press-molding surface, wherein a defect-containing layer formed on the main surface has a thickness of 50 ?m or less.

Abstract: According to one aspect of the present invention, provided is glass for use in substrate for information recording medium, which comprises, denoted as molar percentages, a total of 70 to 85 percent of SiO2 and Al2O3, where SiO2 content is equal to or greater than 50 percent and Al2O3 content is equal to or greater than 3 percent; a total of equal to or greater than 10 percent of Li2O, Na2O and K2O; a total of 1 to 6 percent of CaO and MgO, where CaO content is greater than MgO content; a total of greater than 0 percent but equal to or lower than 4 percent of ZrO2, HfO2, Nb2O5, Ta2O5, La2O3 Y2O3 and TiO2; with the molar ratio of the total content of Li2O, Na2O and K2O to the total content of SiO2, Al2O3, ZrO2, HfO2, Nb2O5, Ta2O5, La2O3, Y2O3 and TiO2 ((Li2O+Na2O+K2O)/(SiO2+Al2O3+ZrO2+HfO2+Nb2O5+Ta2O5+La2O3+Y2O3+TiO2)) being equal to or less than 0.28.

Abstract: [Problem] When heating a glass gob of glass which crystallizes easily to a temperature at which press-molding is possible, there are many cases in which the surface of the glass gob crystallizes and hardens. The problem of surface crystallization of glass gobs when press-molding is particularly prominent with glass to be polished and subjected to press-molding at a high temperature. [Solution] This method for producing a glass molded article includes a step (A) for covering the surface of a glass gob with a covering agent, and a step (B) for heating, softening and molding the glass gob covered by the covering agent. Therein, the covering agent contains components which melts at a temperature equal to or lower than the melting point of the glass configuring the glass gob.

Abstract: When heating a glass gob including optical glass containing phosphorus, oxygen and fluorine to a temperature at which press-molding is possible, there are many cases in which the surface of the glass gob crystallizes and hardens. The problem of surface crystallization of glass gobs when press-molding is particularly prominent with glass to be polished and subjected to press-molding at a high temperature. This method for producing a glass molded article includes a step for covering the surface of a glass gob, which includes optical glass containing phosphorus, oxygen and fluorine, with a covering agent containing phosphorus, and a step for heating, softening and molding the glass gob covered by the covering agent.

Abstract: A glass for use in chemical reinforcement for use in a substrate of an information recording medium, having a composition comprising, denoted as mol %: SiO2 47 to 70%? Al2O3 1 to 10% (where the total of SiO2 and Al2O3 is 57 to 80%) CaO 2 to 25% BaO 1 to 15% Na2O 1 to 10% K2O 0 to 15% (where the total of Na2O and K2O is 3 to 16%) ZrO2 1 to 12% MgO 0 to 10% SrO 0 to 15% (where the ratio of the content of CaO to the total of MgO, CaO, SrO, and BaO is greater than or equal to 0.5) ZnO 0 to 10% (where the total of MgO, CaO, SrO, BaO, and ZnO is 3 to 30%) TiO2 0 to 10% and the total content of the above-stated components is greater than or equal to 95%. A glass for use in chemical reinforcement for use in the substrate of an information recording medium employed in a perpendicular magnetic recording system, in which the glass exhibits the glass transition temperature is greater than or equal to 600° C.

Abstract: According to one aspect of the present invention, provided is glass for use in substrate for information recording medium, which comprises, denoted as molar percentages, a total of 70 to 85 percent of SiO2 and Al2O3, where SiO2 content is equal to or greater than 50 percent and Al2O3 content is equal to or greater than 3 percent; a total of equal to or greater than 10 percent of Li2O, Na2O and K2O; a total of 1 to 6 percent of CaO and MgO, where CaO content is greater than MgO content; a total of greater than 0 percent but equal to or lower than 4 percent of ZrO2, HfO2, Nb2O5, Ta2O5, La2O3 Y2O3 and TiO2; with the molar ratio of the total content of Li2O, Na2O and K2O to the total content of SiO2, Al2O3, ZrO2, HfO2, Nb2O5, Ta2O5, La2O3, Y2O3 and TiO2 ((Li2O+Na2O+K2O)/(SiO2+Al2O3+ZrO2+HfO2+Nb2O5+Ta2O5+La2O3+Y2O3+TiO2)) being equal to or less than 0.28.

Abstract: According to one aspect of the present invention, provided is glass for use in substrate for information recording medium, which comprises, denoted as molar percentages, a total of 70 to 85 percent of SiO2 and Al2O3, where SiO2 content is equal to or greater than 50 percent and Al2O3 content is equal to or greater than 3 percent; a total of equal to or greater than 10 percent of Li2O, Na2O and K2O; a total of 1 to 6 percent of CaO and MgO, where CaO content is greater than MgO content; a total of greater than 0 percent but equal to or lower than 4 percent of ZrO2, HfO2, Nb2O5, Ta2O5, La2O3 Y2O3 and TiO2; with the molar ratio of the total content of Li2O, Na2O and K2O to the total content of SiO2, Al2O3, ZrO2, HfO2, Nb2O5, Ta2O5, La2O3, Y2O3 and TiO2 ((Li2O+Na2O+K2O)/(SiO2+Al2O3+ZrO2+HfO2+Nb2O5+Ta2O5+La2O3+Y2O3+TiO2)) being equal to or less than 0.28.

Abstract: In order to produce a fluorophosphate glass including P5+ at a small content on the composition thereof, the composition is adjusted so as to provide well-balanced chemical durability and thermal stability. In the production of a fluorophosphate glass in which O2?/P5+>3.7, Al3+ content is in a predetermined amount or more and p5+ content is in a predetermined amount or less, a glass raw material is prepared by using an AlF3 in which the content of Al2O3 is limited to the range from 1 to 5% by mass, and the raw material is melted to produce the fluorophosphate glass.

Abstract: Disclosed are a glass substrate for an information recording medium, having excellent scratch resistance and a light weight and having high fracture toughness, the glass substrate having a fragility index value, measured in water, of 12 ?m?1/2 or less or having a fragility index value, measured in an atmosphere having a dew point of ?5° C. or lower, of 7 ?m?1/2 or less, or the glass substrate comprising, by mol %, 40 to 75% of SiO2, 2 to 45% of B2O3 and/or Al2O3 and 0 to 40% of R?2O in which R? is at least one member selected from the group consisting of Li, Na and K), wherein the total content of SiO2, B2O3, Al2O3 and R?2O is at least 90 mol %, and a magnetic information recording medium comprising a magnetic recording layer formed on the glass substrate.

Abstract: An aspect of the present invention relates to a glass substrate for a magnetic recording medium, which is comprised of glass with a glass transition temperature of equal to or greater than 600° C., an average coefficient of linear expansion at 100 to 300° C. of equal to or greater than 70×10?7/° C., a Young's modulus of equal to or greater than 81 GPa, a specific modulus of elasticity of equal to or greater than 30 MNm/kg, and a fracture toughness value of equal to or greater than 0.9 MPa·m1/2.

Abstract: The present invention provides a fluorophosphate glass containing more than 3 cationic % and 30 cationic % or less of a phosphorus ingredient in terms of P5+, the glass having a ratio I(1)/I(0) of equal to or less than 0.08 in which I(0) is a strength of a resonance peak generated near a reference frequency of 31P in a nuclear magnetic resonance spectrum and I(1) is a strength of a first-order side band peak of the resonance peak. The glass of the invention is reduced in volatility and erosiveness.