Patent ID: 6306786
Filing Date: 2001-10-23
Classification: C03C,Y10T

Abstract:
A substrate for information recording media which comprises a glass composition comprising the following basic components in terms of mol %:40 to 65% SiO.sub.2,5 to 25% Al.sub.2 O.sub.3,2 to 20% Li.sub.2 O,0 to 9% Na.sub.2 O,0 to 10% TiO.sub.2,0 to 10% ZrO.sub.2,0 to 25% MgO,0 to 25% CaO, and0 to 10% SrO,provided that the content of RO (RO.dbd.MgO+CaO+SrO) is from 2 to 40% and the sum of (Li.sub.2 O)/2 and Na.sub.2 O is from 1 to 10 mol %, said glass composition further containing from 0.1 to 3.0 mol % SnO.sub.2 and from 0.004 to 0.1 mol % sulfur (S) in terms of the amount of SO.sub.3 and having a rigidity as defined by (Young's modulus)/(specific gravity) of 30 GPa.multidot.g.sup.-1.multidot.cm.sup.3 or higher and a modulus of elasticity as represented by Young's modulus of 90 GPa or higher.