1.1 ,This test method is for the determination of the inherent viscosity of poly(ethylene terephthalate) (PET) soluble at 0.50 ,% concentration in a 60/40 phenol/1,1,2,2-tetrachloroethane solution by means of a glass capillary viscometer. Highly crystalline forms of PET that are not soluble in this solvent mixture will require a different procedure.