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Intermittency in ageing

2003; IOP Publishing; Volume: 15; Issue: 11 Linguagem: Inglês

10.1088/0953-8984/15/11/336

1361-648X

Lionel Buisson, Ludovic Bellon, S. Ciliberto,

Advanced Mathematical Theories and Applications

The fluctuation-dissipation relation (FDR) is measured on the dielectric properties of a gel (Laponite) and of a polymer glass (polycarbonate). For the gel it is found that during the transition from a fluid-like to a solid-like state the fluctuation dissipation theorem is strongly violated. The amplitude and the persistence time of this violation are decreasing functions of frequency. Around $1Hz$ it may persist for several hours. A very similar behavior is observed in polycarbonate after a quench below the glass transition temperature. In both cases the origin of this violation is a highly intermittent dynamics characterized by large fluctuations. The relevance of these results for recent models of aging are discussed.