Abstract: The present invention provides a glass composition not requiring a large quantity of rare earth material, producible by a common apparatus for producing a glass, having a high Young's modulus and a large crack initiation load, and suitable for glass fibers etc. A glass composition according to the present invention contains, in mol %: 50 to 65% SiO2; 7.5 to 26% Al2O3; 15 to 30% MgO; 0 to 8% CaO; 0 to 3% B2O3; 0 to 3% Li2O; and 0 to 0.2% Na2O. In this glass composition, a total content of MgO and CaO is in a range of 18 to 35 mol %, and a mol ratio calculated by Al2O3/(MgO+CaO) is less than 1.

Abstract: A glass fiber according to the present invention is suitable for preventing filament breakage and suitable for being stably produced for a long term, and has a ?-OH value of 0.02 mm?1 or more and less than 0.55 mm?1. The preferred content of SO3 is more than 0 ppm and 70 ppm or less on a mass basis. The glass fiber is preferably substantially free of As and Sb. SO3 can be supplied to a glass raw material as, for example, a sulfuric acid salt of an alkali metal or an alkaline-earth metal.

Abstract: The present invention provides a glass composition not requiring a large quantity of rare earth material, producible by a common apparatus for producing a glass, having a high Young's modulus and a large crack initiation load, and suitable for glass fibers etc. A glass composition according to the present invention contains, in mol %: 50 to 65% SiO2; 7.5 to 26% Al2O3; 15 to 30% MgO; 0 to 8% CaO; 0 to 3% B2O3; 0 to 3% Li2O; and 0 to 0.2% Na2O. In this glass composition, a total content of MgO and CaO is in a range of 18 to 35 mol %, and a mol ratio calculated by Al2O3/(MgO+CaO) is less than 1.

Abstract: A glass for laser processing that is processed through laser beam irradiation, wherein the glass for laser processing has a composition that satisfies the following relationships: 40?M[NFO]?70; 5?(M[TiO2])?45; and 5?M[NMO]?40, where M[NFO], M[TiO2], and M[NMO] denote the content by percentage of network forming oxides (mol %), that of TiO2 (mol %), and that of network modifying oxides (mol %), respectively. With this structure, a glass for laser processing is obtained in which not only the vicinity of the surface thereof but also the inner portion thereof can be laser-processed.

Abstract: The present invention provides a glass for anodic bonding having a low thermal expansion coefficient and capable of being subjected to laser beam micromachining. The present invention is a glass for anodic bonding having a base glass composition containing 1 to 6 mol % of Li2O+Na2O+K2O and having an average linear expansion coefficient of 32×10?7 K?1 to 39×10?7 K?1 in a temperature range of room temperature to 450° C. This glass further contains 0.01 to 5 mol % of a metal oxide as a colorant relative to the base glass composition, and has an absorption coefficient of 0.5 to 50 cm?1 at a particular wavelength within 535 nm or less.

Abstract: A glass processing method comprising steps (i), (ii) carried out in the order mentioned. In step (i), a laser pulse (11) with a wavelength ? is condensed by a lens and is applied to a glass plate (12) to form an altered portion (13) at the portion, irradiated with a laser pulse (11), of the glass plate (12). In step (ii), the altered portion (13) is etched by using an etchant having an etching rate larger for the altered portion (13) than that for the glass plate (12). The laser beam used includes the following conditions: The pulse width of a laser pulse (11) ranges from ins to 200 ns, with a wavelength ? being up to 535 nm. The absorption coefficient of the glass plate (12) at a wavelength ? is up to 50 cm?1. A value obtained from a lens focal distance L (mm) divided by the beam diameter D (mm) of the laser pulse (11) when entering the lens is at least 7.

Abstract: A glass for laser processing that is processed through laser beam irradiation, wherein the glass for laser processing has a composition that satisfies the following relationships: 40?M[NFO]?70; 5?(M[TiO2])?45; and 5?M[NMO]?40, where M[NFO], M[TiO2], and M[NMO] denote the content by percentage of network forming oxides (mol %), that of TiO2 (mol %), and that of network modifying oxides (mol %), respectively. With this structure, a glass for laser processing is obtained in which not only the vicinity of the surface thereof but also the inner portion thereof can be laser-processed.