Refractometric determination of second‐order transition temperatures in polymers. III. Acrylates and methacrylates

A refractometric technique for determination of second‐order transition temperatures ( T m ) of polymers has been extended to include a series of alkyl acrylate and methacrylate polymers with transitions at temperatures down to −50°C. A convenient technique for determining refractive index down to −75°C. is described. Certain long‐chain alkyl polymers are birefringent below T m . Correlations of brittle point with T m and relations between viscosity and T m are reported.