Abstract: A glass plate includes, in terms of molar percentage based on oxides: 50% ? SiO2 ? 80%; 5.0% ? Al2O3 ? 10%; 5.0% < B2O3 ? 15%; 0.0% ? P2O5 ? 10%; 0.0% ? MgO ? 10%; 0.0% ? CaO ? 10%; 0.0% ? SrO ? 10%; 0.0% ? BaO ? 10%; 0.0% ? ZnO ? 5.0%; 0.0% ? Li2O ? 5.0%; 0.0% ? Na2O ? 5.0%; 0.0% ? K2O ? 5.0%; 0.0% ? R2O ? 5.0%; Fe2O3 ? 0.04%; 15% ? RO ? 30%; B2O3 - Al2O3 > 0.0%; and 0.30 < Al2O3/RO < 0.50, in which the glass plate has a temperature T12 at which a glass viscosity is 1012 dPa·s of 730° C. or lower, and the glass plate has an average thermal expansion coefficient at 50° C. to 350° C. of 40 × 10-7/K or more.

Abstract: A borosilicate glass includes, in terms of molar percentage based on oxides: 70.0%?SiO2?85.0%; 5.0%?B2O3?20.0%; 0.0%?Al2O3?3.0%; 0.0%?Li2O?5.0%; 0.0%?Na2O?5.0%; 0.0%?K2O?5.0%; 0.0%?MgO?5.0%; 0.0%?CaO?5.0%; 0.0%?SrO?5.0%; 0.0%?BaO?5.0%; and 0.06%?Fe2O3?1.0%, in which the borosilicate glass has a basicity of 0.485 or more, and [AlO3]/([SiO2]+[B2O3]) of 0.015 or less.

Abstract: Glass contains, in mol percentage on an oxide basis, SiO2: 35% to 60%, B2O3: 0.8% to 8%, Al2O3: 6% to 21%, and MgO: 17% to 44%. Additionally, (MgO/Al2O3)?1 is satisfied, a measured Madelung constant m calculated by an expression (1A) is equal to or larger than 1.05, and a thermal expansion factor as a ratio of a measured value ? of a linear thermal expansion coefficient to a calculated value ?cal of a linear thermal expansion coefficient calculated from composition is equal to or smaller than 0.7. Herein, E is a measured value of a Young's modulus of the glass, Vp is an average atomic packing factor of the glass, and Gt is average bond dissociation energy of the glass.