SUBSTRATE GLASS FOR INFORMATION RECORDING MEDIUM AND METHOD OF MANUFACTURE

摘要

PROBLEM TO BE SOLVED: To provide a substrate glass for an information recording medium wherein the wear of a mold is reduced even the glass is press molded, the adhesion of the glass to the mold can be also prevented and the surface smoothness of the glass is not reduced even if the glass is ion exchanged because of its reduced alkali elution. SOLUTION: The substrate glass for the information recording medium has <=0.3 mg of alkali elution in water resistance measured by following JIS R3502 and <=600 deg.C temperature corresponding to 107.6 poise viscosity.