Borosilicate Glass



Also known as Pyrex, borosilicate glass mainly consists in silica :

- SiO2 : 81%

- B2O3 : 13%

- Na2O : 4%

- AI2O3 : 2%


  • Chemical properties
Borosilicate Glass is resistant to almost all chemicals :

- Hydrolytic resistance :  HGA 1 and HGB 1 Standard
- Acids resistance : S1 Standard
- Alkaline resistance : A2 Standard

Only hydroflouric acid, hot phosphoric acid and hot strong caustic solutions can corrode borosilicate glass significantly.


  • Physical properties
- Thermal expansion coefficient  (α=20-300°C) : 3.3 x 10-6 K-1
- Density (20°C) : 2.23 g.cm-3
- Thermal conductivity (λw=20-100°C) : 1.14 W.m-1.K-1
- Modulus of elasticity E : 64 103 MPa
- Poissons ratio µ (25-400°C) : 0.020
- Refractive index  nD (λ = 587.6 nm) : 1.473
- Permittivity  ε (20°C–1MHz) : 4.56


  • Thermal properties
Borosilicate glass can resist fairly high temperature :

- Minimum operating temperature : - 192°C
- Maximum operating temperature (short lasting) :  500 °C
- Lower cooling temperature :  525 °C
- Softening point  : 825 °C
- Working temperature :  1 260 °C


  • Optical properties
Borosilicate glass is transparent and colourless. It is therefore ideal for photo chemical reactions or work in the visible region of spectrum.
Optical properties of borosilicate glass VS Technologies
 Borosilicate glass is therefore ideal for use in laboratories or industry.