A study of the photoelastic properties of segmented polyurethanes

The photoelastic effect of oligo-oxyethylene blocks in films of segmented polyurethanes of various MMs has been studied. Complicated time dependences of birefringence, when the load was applied and then removed, were found. It was shown that this is connected with the 2-phase morphology of these polymers. Comparison of the experimental values of their optical anisotropy with those calculated from a valency-optical scheme permitted an estimate of the thermodynamic rigidity of the chain.