1.1 This test method is applicable to materials that soften upon heating to a modulus less than 6.0 MPa. This test method describes the determination of the temperature at which the specific modulus of either 6.65 (Method A) or 33.3 MPa (Method B) (equivalent to Test Method D1525) of a test specimen is realized by indentation measurement using a thermomechanical analyzer as the test specimen is heated. This temperature is identified as the indentation softening temperature. The test may be performed over the temperature range of ambient to 300°C.

1.2 This test method is not recommended for ethyl cellulose, poly (vinyl chloride), poly (vinylidene chloride) and other materials having a large measurement imprecision (see Test Method D1525 and 5.3 and Section 14).

1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.4 There is no ISO standard equivalent to this test method.

1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.