Temperature dependent optical properties of a synthesis blends of PMMA and vinyl rubber

The temperature dependent optical properties of a poly(methyl methacrylate) (PMMA) ethylene-co-vinylacetate (EVA) blend (PMMA-EVA) were investigated in order to study its thermo-optical behaviour in the temperature range 30-70?C. The thermal coefficients of the refractive index dn/dt of PMMA-EVA, PMMA and EVA were measured as a function of the temperature. The observed trend of the, thermal coefficients is related to a first-order phase transition of the EVA component. A comparison with the results of calorimetric investigations by differential scanning calorimetry (DSC) is also reported. The possible use of this material in optics is described.