A support glass substrate of the present invention is a support glass substrate for supporting a substrate to be processed, the support glass substrate including lithium aluminosilicate-based glass, having a content of Li.sub.2O of from 0.02 mol % to 25 mol % in a glass composition, and having an average linear thermal expansion coefficient within a temperature range of from 30° C. to 380° C. of 38×10.sup.−7/° C. or more and 160×10.sup.−7/° C. or less.

A glass for magnetic recording medium substrate is an amorphous oxide glass. In terms of mol %, SiO.sub.2 content ranges from 45 to 68%, Al.sub.2O.sub.3 from 5 to 20%, total content of SiO.sub.2 and Al.sub.2O.sub.3 60 to 80%, B.sub.2O.sub.3 from 0 to 5%, MgO from 3 to 28%, CaO from 0 to 18%, total content of BaO and SrO 0 to 2%, total content of alkali earth metal oxides from 12 to 30%, total content of alkali metal oxides from 3.5 to 15%, and at least one kind selected from the group made of Sn oxide and Ce oxide being included, a total content of Sn oxide and Ce oxide ranges from 0.05 to 2.00%, a glass transition temperature ≥625° C., a Young's modulus ≥83 GPa, a specific gravity ≤2.85, and an average linear expansion coefficient at 100 to 300° C.≥48×10.sup.−7/° C.

A glass for magnetic recording medium substrate is an amorphous oxide glass. In terms of mol %, SiO.sub.2 content ranges from 45 to 68%, Al.sub.2O.sub.3 from 5 to 20%, total content of SiO.sub.2 and Al.sub.2O.sub.3 60 to 80%, B.sub.2O.sub.3 from 0 to 5%, MgO from 3 to 28%, CaO from 0 to 18%, total content of BaO and SrO 0 to 2%, total content of alkali earth metal oxides from 12 to 30%, total content of alkali metal oxides from 3.5 to 15%, and at least one kind selected from the group made of Sn oxide and Ce oxide being included, a total content of Sn oxide and Ce oxide ranges from 0.05 to 2.00%, a glass transition temperature ≥625° C., a Young's modulus ≥83 GPa, a specific gravity ≤2.85, and an average linear expansion coefficient at 100 to 300° C.≥48×10.sup.−7/° C.

The present invention relates to a crystallized glass including: at least one crystal of indialite and cordierite, in which the crystallized glass has a total amount of the crystal is 40 mass % or more of the crystallized glass, and the crystal comprises at least one of a vacancy and a different element at an Al site.

The present invention relates to a crystallized glass including: at least one crystal of indialite and cordierite, in which the crystallized glass has a total amount of the crystal is 40 mass % or more of the crystallized glass, and the crystal comprises at least one of a vacancy and a different element at an Al site.

Scratch and damage resistant laminated glass articles are disclosed. According to one aspect, a laminated glass article may include a glass core layer formed from core glass composition and includes a core glass elastic modulus E.sub.C and at least one glass clad layer fused directly to the glass core layer. The at least one glass clad layer may be formed from an ion exchangeable clad glass composition different than the core glass composition and includes a clad glass elastic modulus E.sub.CL. The laminated glass article may have a total thickness T and the at least one glass clad layer may have a thickness T.sub.CL that is greater than or equal to 30% of the total thickness T. E.sub.C may be at least 5% greater than E.sub.CL.

Provided is a glass direct roving that can achieve good productivity for long glass fiber-reinforced thermoplastic resin pellets, and achieve excellent spinning productivity and good strength of glass fiber-reinforced resin molded articles produced by using long glass fiber-reinforced thermoplastic resin pellets in combination. The glass direct roving includes a plurality of glass filaments bundled together, wherein the filament diameter of the glass filaments, D, is in the range of 17.5 to 21.5 μm, the number of the glass filaments bundled, F, is in the range of 3000 to 7000, the mass of the glass direct roving is in the range of 2450 to 4000 tex, the ignition loss of the glass direct roving, L, is in the range of 0.03 to 0.90%, and the D, F, and L satisfy the following formula (1): $\begin{array}{cc}1050\le \left(D^4\times F^{1/4}\right)/\left(1000\times L^{1/6}\right)\le 1640.& \left(1\right)\end{array}$

The present invention relates to a glass for a pharmaceutical container that is excellent in ultraviolet shielding ability, and is also excellent in chemical durability. The glass for a pharmaceutical container of the present invention includes as a glass composition, in terms of mass %, 67% to 81% of SiO.sub.2, more than 4% to 7% of Al.sub.2O.sub.3, 7% to 14% of B.sub.2O.sub.3, 3% to 12% of Na.sub.2O+K.sub.2O, 0% to 1.8% of CaO+BaO, 0.5% to less than 2% of Fe.sub.2O.sub.3, and 1% to 5% of TiO.sub.2, and satisfies a relationship of CaO/BaO≤0.5.

The present invention relates to a glass for a pharmaceutical container that is excellent in ultraviolet shielding ability, and is also excellent in chemical durability. The glass for a pharmaceutical container of the present invention includes as a glass composition, in terms of mass %, 67% to 81% of SiO.sub.2, more than 4% to 7% of Al.sub.2O.sub.3, 7% to 14% of B.sub.2O.sub.3, 3% to 12% of Na.sub.2O+K.sub.2O, 0% to 1.8% of CaO+BaO, 0.5% to less than 2% of Fe.sub.2O.sub.3, and 1% to 5% of TiO.sub.2, and satisfies a relationship of CaO/BaO≤0.5.

A glass-ceramic that includes a first crystal phase including (Mg.sub.xZn.sub.1-x)Al.sub.2O.sub.4, where x is ≤1, and a second crystal phase including tetragonal ZrO.sub.2. The glass-ceramic may be substantially free of arsenic, tin, antimony, and cesium, each of the arsenic, tin, antimony, and cesium present at less than 0.01% (by mole of oxide). Further, the glass-ceramic may include a transmittance of at least about 80% to light having a wavelength of 380 nm to 760 nm.