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温度・粘度
softening point
Japanese: 軟化点
Approximate temperature at which glass begins to deform under its own weight (log η ≈ 7.6). This is around the lower limit for tack fusion. / Note: Defined in ASTM C338. For soda-lime glass, this is around 660–700°C.
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The softening point is a measure of the temperature at which glass begins to deform under its own weight, and corresponds to a viscosity of log η ≈ 7.6 (as defined in ASTM C338).
For soda-lime glass, this is around 660 to 700°C, which corresponds to the lower limit of tack fusion.
This entry is written in Japanese by Rei Chikaoka and translated for readers outside Japan. If something reads oddly, the original is the source of truth.