Tempered Glass
Definition
Glass heat-treated to introduce compressive surface stresses and tensile core stresses, producing a material four to five times stronger than annealed glass that fractures into small cuboid dice rather than large sharp shards.
- Strength multiplier
- 4-5 times stronger than annealed glass
- Fracture pattern
- Small cuboid dice instead of large sharp shards
- Treatment methods
- Thermal or chemical toughening
Common questions
What happens when tempered glass breaks?+
Tempered glass fractures into small, blunt, dice-like cubes called dicing, rather than sharp shards. This is the defining characteristic that makes it safer than ordinary glass.
Why is tempered glass stronger than regular glass?+
Tempered glass is heat-treated or chemically toughened to create compressive stresses on the surface and tensile stresses in the core. This gives it four to five times the strength of annealed glass.
Where is tempered glass commonly used?+
Tempered glass appears in car side windows, shower screens, and mobile phone screen protectors. Its safety profile makes it the standard choice anywhere broken glass poses a risk.
Related terms
- ASTM E2927
- Standard test method for the determination of trace elements in glass samples using LA-ICP-MS; specifies the element suite, calibration standards (NIST SRM...
- Borosilicate Glass
- Heat-resistant glass with about 80 percent SiO2 and 13 percent B2O3 (boric oxide). Low thermal expansion. Used in cookware (Borosil, Pyrex) and...
- Concentric Crack
- A crack that runs in roughly circular arcs around the point of impact, joining radial cracks. The 4C rule applies: Concentric cracks...
- ENFSI ENG3-2013
- The ENFSI Glass Expert Working Group guideline for glass comparison casework; specifies the examination sequence, within-source variation requirements, statistical comparison framework, and...
- Float (Pilkington) Glass
- Sheet glass manufactured on a bath of molten tin. The tin-contact face fluoresces under short-wave UV, which lets the analyst orient a...
- Float Process
- The Pilkington 1959 manufacturing method in which molten glass is poured onto a bath of molten tin, producing a ribbon with two...
- Glass-Transition Temperature (Tg)
- The temperature below which a glass behaves as a rigid solid rather than a viscous liquid; a fundamental thermal property that varies...
- LA-ICP-MS
- Laser ablation inductively coupled plasma mass spectrometry; a technique that fires a laser pulse at a sample surface, vaporises a tiny amount,...
- Laminated Glass
- Two glass sheets bonded with a polyvinyl butyral (PVB) interlayer. Cracks but does not shatter. Standard for windshields and bank counters. The...
- Network Former
- Oxide (SiO2, B2O3, Al2O3) that forms the tetrahedral backbone of a glass network by sharing bridging oxygen atoms between units.
- Network Modifier
- Metal oxide (Na2O, CaO, K2O, PbO, MgO) that introduces cations into the glass network, breaks Si-O-Si bridging bonds, and lowers the melt...
- PVB Interlayer
- Polyvinyl butyral film bonding the two glass layers in a laminated automotive windshield; retains broken glass in place after fracture, preserving the...
Explained in these topics
- Glass: Composition, Types, Fractures and ExaminationThermally or chemically toughened glass that breaks into small, blunt, dice-like cubes (called dicing) instead of shards. Used in car side windows, shower scre...
- Glass: Types, Properties and ManufactureGlass heat-treated to introduce compressive surface stresses and tensile core stresses, producing a material four to five times stronger than annealed glass th...