This document specifies two methods for evaluating the melting behaviour of semi-crystalline polymers. a) Method A: Capillary tube This method is based on the changes in shape of the polymer. It is applicable to all semi-crystalline polymers and their compounds. NOTE 1   Method A can also be useful for the evaluation of the softening of non-crystalline solids. b) Method B: Polarizing microscope This method is based on changes in the optical properties of the polymer. It is applicable to polymers containing a birefringent crystalline phase. It might not be suitable for plastics compounds containing pigments and/or other additives which can interfere with the birefringence of the polymeric crystalline zone. NOTE 2   Another method applicable to semi-crystalline polymers is described in ISO 11357‑3.