Glass transition temperature
The midpoint in the temperature range for which a material reversibly changes from a rigid, solid material to a soft, elastic material. Along with the physical change from stiff to flexible, the material undergoes other changes in thermal expansion and heat capacity. These changes can be measured by thermal analysis methods (DSC, TMA, etc.) to determine the glass transition temperature of the material. A material that is flexible, viscous or rubbery above its glass transition temperature may be hard, inflexible or brittle at temperatures below this point. In general, adhesives perform better above their glass transition point while coatings perform better at temperatures below their glass transition point.
Synonyms and Related Terms
Tg; Glastemperatur (Deut.); température de transition de phase vitreuse (Fr.);