Molecular mobility in polystyrene‐poly(methyl vinyl ether) blends as studied by fluorescence polarization

Molecular motions in different blends of polystyrene with poly(methyl vinyl ether) were investigated by fluorescence polarization measurements on small amounts of dimethylanthracene‐labeled polystyrene chains added to the system. The temperature dependence of the mobility parameter of the label was studied within the DSC glass transition and phase coexistence temperature range. Experimental data fit an expression of the WLF type, in which C1 and C2 values are roughly independent of blend composition and differ to a small extent from the ‘universal’ coefficients. Moreover, mobility determinations suggest the existence of composition micro‐heterogeneities in the blends below their phase coexistence temperature Tc when subjected to long annealing around Tc – 25°C or above.