Standards:
DIN ISO 306
ASTM D1525
or corresponding standards
Vicat
Vicat softening temperature (VST)
The Vicat softening temperature is the temperature at which a standard indenter penetrates 1mm into the surface of a plastic test specimen, under a constant load when the temperature is raised at a uniform rate.
A distinction is drawn between: Method A = 10 N load, Method B = 50 N load,
and rates of increase in temperature from 50K/h or 120 K/h.