Vicat

The Vicat softening temperature (VST), also known as the Vicat softening point, is a measure of the heat resistance or heat deflection temperature of a material, particularly plastics. It is defined as the temperature at which a standardized indenter penetrates a specified distance into the surface of a test specimen under a specific load. This temperature is used to assess the softening or deformation behavior of thermoplastic materials when subjected to heat.