Dynamical Heterogeneity of Glass-forming Polymers: Non-Gaussian Behavior. A Study on Distribution of Mean Square Displacement

摘要

Distinct deviation from the Gaussian approximation was found in the Q dependence of incoherent elastic neutron scattering intensity of a glass-forming polymer, poly(methyl methacrylate). This non-Gaussian behavior was interpreted in terms of a distribution of the mean square displacement, which is caused by the heterogeneity due to different local environments around molecules in the glassy state. In order to see the nature of the distribution, we have examined three distribution functions; Gaussian, log-Gaussian and bimodal distribution functions.