Vicat softening temperature of plastics is the temperature at which a standard flat-ended indentor penetrates one millimetre into the surface of the material under test under a specified load. The test is conducted by placing a test specimen taken from the sample under test on a flat platform inside a liquid bath and applying compression load over its upper face through a flat-ended indentor. The load is applied by placing dead weights on the upper end of the indentor. After the test specimen attains the temperature of the bath, the bath temperature is increased gradually till the indentor penetrates by exactly 1 mm into the test specimen. The bath temperature in degrees centigrade at which this happens is reported as the Vicat Softening Temperature of the sample under test.