Revealing the fast atomic motion of network glasses.
Still very little is known on the relaxation dynamics of glasses at the microscopic level due to the lack of experiments and theories. It is commonly believed that glasses are in a dynamical arrested state, with relaxation times too large to be observed on human time scales. Here we provide the experimental evidence that glasses display fast atomic rearrangements within a few minutes, even in the deep glassy state. Following the evolution of the structural relaxation in a sodium silicate glass, we find that this fast dynamics is accompanied by the absence of any detectable aging, suggesting a decoupling of the relaxation time and the viscosity in the glass. The relaxation time is strongly affected by the network structure with a marked increase at the mesoscopic scale associated with the ion-conducting pathways. Our results modify the conception of the glassy state and asks for a new microscopic theory.
ESRF - The European Synchroton, CS 40220, 38043 Grenoble Cedex 9, France.
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0000000212400533
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Ruta
IMEM-CNR Institute, Parco Area delle Scienze, I-43124 Parma, Italy.
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G
Baldi
ESRF - The European Synchroton, CS 40220, 38043 Grenoble Cedex 9, France.
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Y
Chushkin
1] Université Montpellier 2, Laboratoire Charles Coulomb UMR 5221, F-34095 Montpellier, France [2] CNRS, Laboratoire Charles Coulomb UMR 5221, F-34095 Montpellier, France.
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Rufflé
Physics and Earth Sciences Department, Parma University, I-43124 Parma, Italy.
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Cristofolini
Dipartimento di Fisica, Trento University, Povo, Trento I-38123, Italy.
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Fontana
Dipartimento di Fisica e Geologia, Universitá di Perugia, I-06123 Perugia, Italy.
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Zanatta
Department of Physics, University of Fribourg, Chemin du Musée 3, 1700 Fribourg, Switzerland.
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Nazzani