| 摘要 |
A method of producing a glass substrate for an inforamtion recordeing medium either by press-molding molten glass obtained from glass containing 0.1 to 30 mol.% of TiO2. 1 to 45 mol.% of CaO, 5 to 40 mol.% of the sum of MgO and CaO described above, 3 to 30 mol.% of the sum of Na2O and Li2O. 0 to 15 mol.% of Al2O3 and 35 to 65 mol.% of SiO2 and having a liquidus temperature of not higher than 1,360 DEG C, a viscosity of at least 10 poises within a moldable temperature range and a transition point temperature of lower than 700 DEG C, or by preparing a preform of glass containing 0.1 to 30 mol.% of TiO2, 1 to 45 mol.% of CaO, 5 to 40 mol.% of the sum of MgO and CaO described above, 3 to 30 mol.% of the sum of Na2O and Li2O, 0 to 15 mol.% of Al2O3 and 35 to 65 mol.% of SiO2 and having a liquidus temperature of not higher than 1,360 DEG C, and shaping the preform into a disk by re-heat pressing.
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