| 摘要 |
PROBLEM TO BE SOLVED: To provide a glass for use in a substrate for an information recording medium, a substrate for an information recording medium, an information recording medium, and their production methods.SOLUTION: The glass for use in a substrate for an information recording medium is provided which contains : one or more kinds of alkali metal oxides composed of SiO, AlO, LiO, NaO, and KO; one or more kinds of alkali earth metal oxides composed of MgO, CaO, SrO, and BaO; and one or more kinds of oxides composed of ZrO, HfO, NbO, TaO, LaO, YOand TiO, and in which, denoted as molar percentages, the content of SiOis equal to or greater than 50%, the total of SiOand AlOis equal to or greater than 70%, the total content of the alkali metal oxides and the alkali earth metal oxides is equal to or greater than 8%, and the molar ratio of a total content of the oxides to a total content of the alkali metal oxides and the alkali earth metal oxides is equal to or greater than 0.035.SELECTED DRAWING: None |
