Münster 1997 – wissenschaftliches Programm
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DY: Dynamik und Statistische Physik
DY 12: Gl
äser II
DY 12.9: Vortrag
Dienstag, 18. März 1997, 16:30–16:45, R4
Freezing effects in a simulated polymer melt: analysis of multi-time correlation functions — •Andreas Heuer1 and Katrin Okun2 — 1MPI f. Polymerforschung, Ackermannweg 10, 55128 Mainz — 2Institut für Physik, Univ. Mainz, Staudinger Weg 7, 55099 Mainz
In general, non-exponential relaxation can result either from a heterogeneous (superposition of different exponential processes) or a homogeneous scenario (identical intrinsically non-exponential processes). A numerical procedure is presented which allows to estimate the heterogeneous and homogeneous contributions to the non-exponentiality, i.e. the type of relaxation. The basic idea is to analyse three-time correlation functions. The type of relaxation can be calculated analytically for the Rouse model. Furthermore the type of relaxation is determined for the dynamics of a simulated polymer melt above the glass transition. For short lengthscales and/or low temperatures the dynamics of the polymer melt contains significant heterogeneous contributions in contrast to the Rouse prediction. This is a direct indication of the relevance of local intermolecular interactions for the polymer dynamics. The relevance of the present results for understanding the universality of the glass transition is indicated.