| 摘要 |
PROBLEM TO BE SOLVED: To provide press molding glass easily meltable, easily press molded, enabling a delicate plane following a press mold to be formed, also difficultly loosing shape and capable of raising the degree of so-called chemical reinforcement through alkali ion-exchange. SOLUTION: This press molding glass and substrate glass for an information recording medium based on the same have a composition comprising 58-65 wt.% SiO2 10-15 wt.% Al2O3, 4-6 wt.% Li2O, 10-13 wt.% Na2O, 0-3 wt.% K2O, 0-4 wt.% MgO, 0-4 wt.% CaO, 0-2 wt.% SrO, 1-10 wt.% BaO, 0-5 wt.% TiO2 and 1-5 wt.% ZrO2. The glass is subjected to press molding in a heat molten state and the molded product is chemically reinforced by alkali ion-exchange.
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