Abstract: The thermo-mechanical spectra for vinylchloride-vinylacetate(VC-VAc) copolymer and four vinylchloride-vinylacetate-yinylalcohol (VC-VAc-VA) terpolymer, in which-the molecular weight is similar, but the VAcontent is different, were determined by torsional braid analysis. At the same time, we also measured the thermo-mechanical spectra for several crosslin-ked systems composed of four terpolymer (VC-VAc-VA) and 4, 4'-diphe-nylmethane diisocyanate with stoichiometric and non-stoichiometric amounts of hydroxyl and isocyanate group. The hydrolysis of (VC-VAc) copolymer, which led to occuring of the hydroxyl group, has -definite effect on the glass transition temperature, but the effect of crosslinking on the glass transition temperature is more strong.For the crosslinked system with stoichiometric amounts of hydroxyl and isocyanate group the crosslinked density presented the linear relation with the glass transition temperature, however for the crosslinked system with non-stoichiometric amounts, the relation between the crosslinked density and the glass transition temperature was more complex.