The thermal expansion coefficient of quartz glass is only 1/10 to 1/20 of ordinary glass. The purity of quartz glass has an effect on the expansion coefficient. The linear expansion coefficient of the general transparent quartz glass （0-100℃） is 5.4×10-7. Opaque quartz glass is 5.5×10-7. High purity synthetic quartz glass is 4.9×10-7（0-200℃）-5.0×10-7（5-35℃）.
| Temperature(℃) | 100 | 200 | 300 | 400 | 500 | 600 | 700 | 800 | 900 | 1000 |
|---|---|---|---|---|---|---|---|---|---|---|
| Linear expansion coefficient(×10-7) | 5.10 | 5.85 | 6.27 | 6.35 | 6.12 | 6.00 | 5.71 | 5.62 | 5.56 | 5.42 |
