Europhys. Lett.
Volume 63, Number 4, August 2003
Page(s) 603 - 609
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 01 November 2003
DOI: 10.1209/epl/i2003-00551-4
Europhys. Lett., 63 (4) , pp. 603-609 (2003)

Intermittent origin of the large violations of the fluctuation-dissipation relations in an aging polymer glass

L. Buisson, S. Ciliberto and A. Garcimartín

Ecole Normale Supérieure de Lyon, Laboratoire de Physique, CNRS UMR5672 46 Allée d'Italie, 69364 Lyon Cedex 07, France

(Received 13 May 2003; accepted in final form 10 June 2003)

The fluctuation-dissipation relation (FDR) is measured on the dielectric properties of a polymer glass (polycarbonate) in the range 20 $\un{mHz}$-100 $\un{Hz}$. It is found that after a quench below the glass transition temperature, the fluctuation-dissipation theorem is strongly violated. The amplitude and the persistence time of this violation are decreasing functions of frequency. At frequencies larger than 1 $\un{Hz}$ it persists for about 3 $\un{h}$. The origin of this violation is a highly intermittent dynamics characterized by large fluctuations. The relevance of these results for recent models of aging dynamics is discussed.

75.10.Nr - Spin-glass and other random models.
77.22.Gm - Dielectric loss and relaxation.
64.70.Pf - Glass transitions.

© EDP Sciences 2003