Drawing No. EH–MT–014 // Engineering Materials
Glass Properties
Reviewed August 2026
Annealed soda-lime-silicate float glass is used as the reference. Its elastic modulus is well defined, but practical strength is governed by surface flaws, edge condition, size, load duration and strengthening treatment.
Representative properties
Switch units without changing the underlying material reference.
What changes these properties?
Engineering variability
- Annealed, heat-strengthened and fully tempered glass have very different usable strengths while retaining similar elastic modulus.
- Surface scratches and edge damage can dominate fracture strength.
- Pilkington ATS-129 gives the reference physical-property basis used here; thermal shock still depends on gradients, restraint, thickness, edge condition and flaw state.
- Soda-lime glass is amorphous; softening/annealing/working points are more meaningful than a single melting temperature.
Selection note
For glazing and structural glass, use the applicable glass standard and strength model rather than a generic tensile-strength number.
Do not combine strength from one grade/condition with modulus, thermal data or temperature limits from another without checking compatibility. Where the overview shows a range, it is intended to expose variability—not establish allowable bounds.
Property interpretation
Stiffness vs strength
Young’s modulus controls elastic deformation. Yield or fracture strength controls how far the material can be stressed. These are separate material characteristics.
Thermal response
Thermal conductivity controls temperature gradients, specific heat contributes to thermal inertia, and expansion controls thermally induced strain when movement is restrained.
Temperature transition
The final property card is deliberately labeled “melting / transition.” Metals often have a solidus–liquidus range; amorphous polymers and glass use softening or glass-transition concepts; concrete and wood decompose instead of exhibiting one clean melt point.
Technical sources
Source hierarchy favors manufacturers, industry associations, standards bodies and government engineering references. Strength data must still be reconciled with the exact procurement specification.