Menu (ESC)

Toughened (Tempered) Soda-Lime Glass

Tempered soda-lime glass is a grade of soda-lime glass. The graph bars on the material properties cards below compare tempered soda-lime 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

Elastic (Young's, Tensile) Modulus

70 GPa 10 x 106 psi

Knoop Hardness


Poisson's Ratio


Shear Modulus

29 GPa 4.1 x 106 psi

Tensile Strength: Ultimate (UTS)

180 MPa 25 x 103 psi

Thermal Properties

Maximum Temperature: Mechanical

300 °C 570 °F

Specific Heat Capacity

720 J/kg-K 0.17 BTU/lb-°F

Thermal Conductivity

1.1 W/m-K 0.61 BTU/h-ft-°F

Thermal Expansion

9.0 µm/m-K

Electrical Properties

Dielectric Constant (Relative Permittivity) At 1 MHz


Dielectric Strength (Breakdown Potential)

13 kV/mm 0.51 V/mil

Otherwise Unclassified Properties


2.4 g/cm3 150 lb/ft3

Light Transmission Range

0.35 to 2.5 µm

Refractive Index


Common Calculations

Stiffness to Weight: Axial

16 points

Stiffness to Weight: Bending

56 points

Strength to Weight: Axial

20 points

Strength to Weight: Bending

28 points

Thermal Diffusivity

0.6 mm2/s

Thermal Shock Resistance

20 points

Followup Questions

Further Reading

Glass Construction Manual, Christian Schittich et al., 1999

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

Glass: Mechanics and Technology, Eric Le Bourhis, 2007