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SY: Von der Flüssigkeit zum Glas

SY XI: HV XI

SY XI.1: Invited Talk

Thursday, March 20, 1997, 10:00–10:30, S 8

Dynamic Structure Factor in the Merging Region of the Alpha- and Beta-Relaxations in Polymers — •Arantxa Arbe Mendez — Departamento de Fisica de Materiales, Universidad del Pais Vasco, San Sebastian

The local dynamics of glass-forming polymers below and above the merging of the alpha- and beta-relaxations have been investigated by means of Neutron Spin Echo (NSE) over a wide Q-range, covering inter- as well as intra-chain regions. Exploiting the Q-dependence of the coherent dynamic structure it became possible: (1) At temperatures below the merging temperature to obtain spatial information on the chain motions behind the beta-relaxation. (2) At temperatures around the merging and above the NSE experiments qualified the alpha-relaxation as being a diffusive process mainly related to interchain motions. (3) The dynamic structure factor above the merging can consistently be described assuming that alpha- and beta-relaxations in these polymers are statistically independent processes.