| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of forming quartz glass which is capable of preventing the generation of air bubbles and devitrification in a formed ingot. SOLUTION: This method of forming the quartz glass comprises putting a quartz glass ingot into a forming die housed into a smelting furnace and reducing the pressure in the furnace while introducing inert gas therein from the upper part of the furnace in a temperature region of an in-furnace temperature from 900 to 1,300 deg.C, then keeping the in-furnace temperature at >=1,500 deg.C for a prescribed time and forming the quartz glass ingot to a formed body and expelling the air bubbles included in the formed body.
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