Time-dependent non-gaussianity of glassy copolyester observed through elastic incoherent neutron scattering

Complete text of publication follows. The dynamical heterogeneity of glasses gives rise to different mean square displacements a of different atoms indifferent directions. The simplest way to measure it is a measurement of the incoherent elastic neutron scattering as a function of the momentum vector Q. As the dynamical heterogeneity becomes stronger, the deviation from a simple exp(-αQ2) law becomes more obvious. As long as the deviations are small, one can describe these deviations by the expression exp(-αQ2+α2A0Q2/2), where the nongaussianity A0 is a dimensionless measure of the mean square deviation of the mean square displacement of different atoms. In this presentation, time-dependent observations on the nongaussianity A0 are presented which has been performed by changing the energy resolution of spectrometers. (author)