| 摘要 |
The present invention has for its objects to provide a method for manufacturing a disklike glass material for the mass production of information recording media substrate-use materials of constant sheet thickness, to provide a method for manufacturing an information recording medium-use substrate from the material thus manufactured, and to provide a method for manufacturing an information recording medium. The provided is a method for manufacturing a disklike glass material comprising the successive molding of multiple pieces of disklike glass material from glass melt. Being suppressed variation over time in the concentration of infrared radiation-absorbing ions contained in the glass melt being molded into said pieces of disklike glass material so that the variation in the sheet thickness of said multiple pieces of disklike glass material falls within a range of ±15 percent of a reference value. The reference value being the median between the maximum value and the minimum value of the sheet thickness of 1,000 pieces of said glass material. In the course of molding multiple pieces of disklike glass material comprised of glass containing 0.1 to 100 ppm of infrared radiation-absorbing ions, variation over time in the concentration of the infrared radiation-absorbing ions contained in the glass melt being molded into said pieces of disklike glass material is suppressed to suppress variation in the sheet thickness of said multiple pieces of sheetlike glass material.
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