The information recording medium and the substrate and method of manufacturing the same

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According the present invention, there is provided a glass for use in substrate for information recording medium, which comprises SiO 2 ; Al 2 O 3 ; one or more alkali metal oxides selected from the group consisting of Li 2 O, Na 2 O and K 2 O; one or more alkaline earth metal oxides selected from the group consisting of MgO, CaO, SrO and BaO; and one or more oxides selected from the group consisting of ZrO 2 , HfO 2 , Nb 2 O 5 , Ta 2 O 5 , La 2 O 3 , Y 2 O 3 and TiO 2 ; wherein the contents of various components, in molar percent, are as follows : SiO 2 : ‰¥ 50, Al 2 O 3 : ‰¥ 3, SiO 2 + Al 2 O 3 : 70 to 85; Li 2 O : ‰¥ 4.3, Na 2 O : ‰¥ 5, Li 2 O + Na 2 O : ‰¤ 24; alkali metal oxides + alkaline earth meal oxides : > 8; MgO : < 3, CaO : ‰¤ 4; and the molar ratios of various components are as follows : ((ZrO 2 + HfO 2 + Nb 2 O 5 + Ta 2 O 5 + La 2 O 3 + Y 2 O 3 + TiO 2 )/(Li 2 O + Na 2 O + K 2 O + MgO + CaO + SrO + BaO)) : ‰¥ 0.035; (MgO/CaO) : 0.130 to 0.700. Further provided are a substrate for information recording medium, an information recording medium and their manufacturing methods.