Glass — Thermal Expansion, Glass Transition, Softening

Coefficients of thermal expansion (Coefficient of Linear Thermal Expansion (CLTE/CTE)The coefficient of linear thermal expansion (CLTE) describes the length change of a material as a function of the temperature.CTE), Glass Transition TemperatureThe glass transition is one of the most important properties of amorphous and semi-crystalline materials, e.g., inorganic glasses, amorphous metals, polymers, pharmaceuticals and food ingredients, etc., and describes the temperature region where the mechanical properties of the materials change from hard and brittle to more soft, deformable or rubbery.glass transition temperatures and softening points are crucial parameters for the characterization of glass materials.

Presented in the figure are three tests on the same type of glass but from different batches. It can clearly be seen that the coefficients of thermal expansion are in good agreement within the instrument’s uncertainty boundaries. The glass transition temperature and the softening point of sample #3 (blue curve) show slightly lower values, indicating a slightly different composition. (measurement with DIL 402 PC)