METHOD FOR MANUFACTURING GLASS SUBSTRATE FOR MAGNETIC INFORMATION RECORDING MEDIUM

摘要

PROBLEM TO BE SOLVED: To provide a method for manufacturing a glass substrate for a magnetic information recording medium, which can suppress the occurrence of undulation and smoothness and secure characteristics necessary as a glass substrate for a magnetic information recording medium while being capable of reducing the processing time by improving the processing rate in a grinding step and a polishing step.

SOLUTION: The method for manufacturing a glass substrate for a magnetic information recording medium includes a step of heat treating a glass substrate at a heat treatment temperature to promote compositional fluctuation in a glass composition capable of making a glass have the compositional fluctuation, and a step of removing at least a part of a phase having a low concentration of SiO2separated by the heat treatment to thereby improve the processability of the surface, wherein the heat treatment temperature is in the range of Tg to Tg+100(°C) where the glass transition temperature of the glass substrate is Tg(°C).

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