Borosilicate Glass
Borosilicate glass is a glass-type material.
The properties of borosilicate glass include four common variations. This page shows summary ranges across all of them. For more specific values, follow the links immediately below. The graph bars on the material properties cards further below compare borosilicate glass to other glass and glass-ceramics (top) and the entire database (bottom). A full bar means this is the highest value in the relevant set. A half-full bar means it's 50% of the highest, and so on.
Mechanical Properties
Compressive (Crushing) Strength
2000 MPa 290 x 103 psi
Elastic (Young's, Tensile) Modulus
67 to 80 GPa 9.7 to 12 x 106 psi
Flexural Strength
34 to 69 MPa 4.9 to 10 x 103 psi
Fracture Toughness
0.8 MPa-m1/2 0.73 x 103 psi-in1/2
Knoop Hardness
510
Poisson's Ratio
0.21
Tensile Strength: Ultimate (UTS)
280 MPa 41 x 103 psi
Thermal Properties
Maximum Temperature: Mechanical
360 °C 680 °F
Maximum Thermal Shock
160 °C 320 °F
Melting Onset (Solidus)
560 °C 1040 °F
Specific Heat Capacity
830 J/kg-K 0.2 BTU/lb-°F
Thermal Conductivity
1.2 W/m-K 0.68 BTU/h-ft-°F
Thermal Expansion
3.3 to 5.1 µm/m-K
Electrical Properties
Dielectric Constant (Relative Permittivity) At 1 Hz
4.8 to 5.5
Dielectric Constant (Relative Permittivity) At 1 MHz
5.4
Dielectric Strength (Breakdown Potential)
5.0 to 34 kV/mm 0.2 to 1.3 V/mil
Electrical Dissipation At 1 Hz
0.0026 to 0.018
Electrical Dissipation At 1 MHz
0.0017 to 0.0088
Electrical Resistivity Order of Magnitude
9.0 to 12 10x Ω-m
Otherwise Unclassified Properties
Density
2.2 to 2.6 g/cm3 140 to 160 lb/ft3
Light Transmission Range
0.3 to 2.5 µm
Refractive Index
1.5
Common Calculations
Stiffness to Weight: Axial
15 to 17 points
Stiffness to Weight: Bending
55 to 61 points
Strength to Weight: Axial
30 to 35 points
Strength to Weight: Bending
36 to 43 points
Thermal Diffusivity
0.54 to 0.63 mm2/s
Thermal Shock Resistance
50 to 91 points
Followup Questions
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
Ceramics and Composites: Processing Methods, Narottam P. Bansal and Aldo R. Boccaccini (editors), 2012
IEC 60672-3: Ceramic and glass-insulating materials - Part 3: Specifications for individual materials