Borosilicate Glass

Borosilicate glass is a glass-type material.

It has four common variants, each represented as a separate material.

Material Properties

Compressive (Crushing) Strength2000 MPa (290 x 103 psi)

Density2.2 to 2.6 g/cm3 (140 to 160 lb/ft3)

Dielectric Constant (Relative Permittivity)4.6 to 5.5

Dielectric Strength (Breakdown Potential)35 kV/mm (1.4 V/mil)

Elastic (Young's, Tensile) Modulus68 to 81 GPa (9.9 to 12 x 106 psi)

Electrical Resistivity Order of Magnitude12 10x Ω-m

Flexural Strength35 MPa (5.1 x 103 psi)

Fracture Toughness0.8 MPa-m1/2

Knoop Hardness510

Light Transmission Range0.3 to 2.5 µm

Maximum Thermal Shock160 °C (320 °F)

Melting Onset (Solidus)560 °C (1040 °F)

Poisson's Ratio0.21

Refractive Index1.5

Specific Heat Capacity830 J/kg-K

Strength to Weight Ratio130 to 110 kN-m/kg

Tensile Strength: Ultimate (UTS)280 MPa (41 x 103 psi)

Thermal Conductivity1.2 W/m-K

Thermal Diffusivity0.56 to 0.66

Thermal Expansion3.3 to 5.1 µm/m-K

Further Reading

ASTM E438: Standard Specification for Glasses in Laboratory Apparatus

Dictionary of Glass: Materials and Techniques, Charles Bray, 2002

Glass: Mechanics and Technology, Eric Le Bourhis, 2007

Handbook of Optical Constants of Solids, Edward D. Palik (editor), 1998

IEC 60672-3: Ceramic and glass-insulating materials - Part 3: Specifications for individual materials