Thermally resistant oven door made with BOROFLOAT® 33 glass.

Thermal Properties

Only the temperature fluctuates

A particularly low coefficient of thermal expansion is what makes BOROFLOAT® glass remarkably resistant to high temperature levels. Our borosilicate glass is proven to stand up to high and fluctuating temperatures typical of applications such as high-performance lamps, cinema projectors and inspection panels for chemical reactors. Even with applications where rapid cooling down from higher temperatures is the requirement, BOROFLOAT® glass easily passes the test. For example, the temperature difference between a hot panel center and a cold panel edge.

Key benefits:

Outstanding thermal resistance
  • Very good temperature stability
  • Excellent resistance to thermal shock
  • Can be thermally toughened
  • Can be thermally shaped (3D)
Thermal properties
Coefficient of Linear Thermal Expansion (C.T.E.) α (20 - 300 °C) 3.25 x 10-6 K-1 *
Specific heat capacity cp (20 - 100 °C) 0.83 kJ/(kg·K)
Thermal conductivity λ (90 °C) 1.2 W/(m·K)

* According to ISO 7991.
Maximum operating temperatures
For short-term usage (< 10 h)
500 °C
For long-term usage (≥ 10 h) 450 °C
Viscosity of BOROFLOAT® 33
Working Point (104 dPas)
1270 °C
LITTLETON temperature / Softening Point (107,6 dPas) 820 °C
Annealing Point (1013 dPas) 560 °C
Strain Point (1014,5 dPas) 518 °C
Transformation temperature (Tg) 525 °C
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