The rate memory of a polymer close toT gas elucidated by reduced 4-D NMR echo experiments

Abstract

We analyze the reorientational dynamics of a polymer close to the glass transition. Via comparison of two-time and four-time correlation functions, obtained from multidimensional nuclear magnetic resonance13C echo experiments, we are particularly sensitive to the fluctuations within the heterogeneous distribution of mobilities. From variation of the experimental parameters we obtain a detailed picture of the interplay between jump and diffusion dynamics, including the different types of motional heterogeneities and the geometry of the system.