| 摘要 |
<p>One embodiment of the present invention relates to a glass for a magnetic recording medium substrate, which contains SiO2, Li2O, Na2O and at least one alkali earth metal oxide selected from the group consisting of MgO, CaO, SrO and BaO as essential components, wherein the molar ratio of the content of CaO relative to the total content of MgO, CaO, SrO and BaO (i.e., (CaO/(MgO+CaO+SrO+BaO)) is 0.20 or less, and the glass transition temperature of the glass is 650°C or higher.</p> |
