Non-Gaussian Parameter and Heterogeneity of Amorphous Polymers

We report neutron scattering experiments on amorphous polymers below and above the glass transition temperature T</it><inf>g</inf> in a wide Q</it> (magnitude of scattering vector) range up to 6.4 Å−1. From the Q</it>-dependence of the incoherent elastic scattering intensity, we have evaluated the non-Gaussian parameter A</it> as functions of temperature and “fragility” of polymers. The results are discussed in terms of dynamical heterogeneity due to different local environments.