How Low Is the Thermal Expansion Coefficient of Borosilicate Glass? A Detailed Look at Its Performance Data

How Low Is the Thermal Expansion Coefficient of Borosilicate Glass? A Detailed Look at Its Performance Data

One of the key reasons borosilicate glass is widely used in laboratories, industry, and high-end consumer products is its remarkably low coefficient of thermal expansion (CTE). This property enables it to withstand extreme and sudden temperature changes without cracking or deforming.

Thermal Expansion Data

• Borosilicate 3.3 Glass (Standard Laboratory Grade):

  • CTE: ~3.3 × 10⁻⁶ /K (from 20°C to 300°C)

  • Thermal Shock Resistance: Can endure temperature differences up to 150–165°C without failure.

• Ordinary Soda-Lime Glass (Common Window Glass):

  • CTE: ~9.0 × 10⁻⁶ /K

  • Thermal Shock Resistance: Typically withstands only 40–60°C temperature differences before risk of cracking.

This threefold difference in CTE explains why borosilicate glass is far more durable under rapid heating or cooling conditions.

Performance Benefits of Low CTE

1. High Thermal Shock Resistance
   Glassware can be moved directly from a hot oven into a cool environment (or vice versa) with minimal risk of cracking.

2. Dimensional Stability
   Components maintain precise dimensions even under fluctuating temperatures — vital for optical instruments and laboratory equipment.

3. Extended Service Life
   Lower internal stress during temperature changes reduces the risk of microcracks, ensuring durability.

4. Versatility in Applications
   From lab beakers and reaction vessels to telescopic mirrors and pharmaceutical vials, borosilicate glass delivers consistent performance.

Conclusion

With a thermal expansion coefficient of just 3.3 × 10⁻⁶ /K, borosilicate glass offers exceptional resistance to temperature changes, far outperforming ordinary glass. This unique property is the foundation of its popularity in high-precision, high-safety applications worldwide.