Patent ID: 8168313
Filing Date: 2012-05-01
Classification: C03C,G11B

Abstract:
1. Glass for an information recording medium substrate, which comprises, as represented by mol % based on the following oxides, from 61 to 72% of SiO 2 , from 3 to 11% of Al 2 O 3 , from 0 to 14.3% of Li 2 O, from 0 to 22% of Na 2 O, from 0 to 22% of K 2 O, from 4 to 13% of MgO, from 0 to 6% of TiO 2 and from 0 to 5% of ZrO 2 , provided that the total content of Li (a) the ratio of the content of Li