| 摘要 |
PROBLEM TO BE SOLVED: To obtain a glass for information recording medium substrate, capable of lightening the substrate hardly causing problems of bending and warpage even in thinning the substrate. SOLUTION: This glass substantially comprises 30-60 mol.% SiO2, 0.5-20 mol.% B2O3, 4-40 mol.% Al2O3, 0-40 mol.% MgO, 0-20 mol.% CaO, 0-6 mol.% Y2O3, 0-20 mol.% TiO2, 0-10 mol.% ZrO2 and 0-12 mol.% Li2O and has <=2.71 g/cm3 density. Preferably, the content of B2O3 shown by mol.% is higher than that of Y2O3 and the specific modulus is >=36 GPa/g/cm3. |
