# 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 10 ^{6} psi*

Knoop Hardness

570

Poisson's Ratio

0.23

Shear Modulus

29 *GPa* 4.1 *x 10 ^{6} psi*

Tensile Strength: Ultimate (UTS)

180 *MPa* 25 *x 10 ^{3} 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

7.3

Dielectric Strength (Breakdown Potential)

13 *kV/mm* 0.51 *V/mil*

## Otherwise Unclassified Properties

Density

2.4 *g/cm ^{3}* 150

*lb/ft*

^{3}Light Transmission Range

0.35 to 2.5 *µm*

Refractive Index

1.5

## 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 *mm ^{2}/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