This part of ISO 16014 specifies a method for determining the average molecular mass and the molecular mass distribution of polymers by size-exclusion chromatography (SEC) using an organic eluent at temperatures between 60 °C and 180 °C. The average molecular mass and the molecular mass distribution are calculated from a calibration curve constructed using polymer standards. Therefore, this test method is classified as a relative method (see ISO 16014-1:2003, Annex A).