Memory in the aging of a polymer glass
Ecole Normale Supérieure de Lyon, Laboratoire de Physique
CNRS UMR5672, 46 Allée d'Italie, 69364 Lyon Cedex 07, France
Accepted: 28 June 2000
Low-frequency dielectric measurements on plexiglass (PMMA) show that cooling and heating the sample at constant rate give a hysteretic dependence on temperature of the dielectric constant ϵ. A temporary stop of cooling produces a downward relaxation of ϵ. Two main features are observed: i) when cooling is resumed ϵ goes back to the values obtained without the cooling stop (i.e. the low-temperature state is independent of the cooling history); ii) upon reheating ϵ keeps the memory of the aging history (Memory). The analogies and differences with similar experiments done in spin-glasses are discussed.
PACS: 64.70.Pf – Glass transitions / 05.20.-y – Classical statistical mechanics / 75.10.Nr – Spin-glass and other random models
© EDP Sciences, 2000