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Dynamic Heterogeneity by Higher Moments of a Relaxing Quantity

Published online by Cambridge University Press:  10 February 2011

R. Richert
R. Richert*
Affiliation:
Max-Planck-Institut fur Polymerforschung, Ackermannweg 10, D-55128 Mainz, Germany
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Abstract

A relaxation experiment usually acquires a measure for the mean energetic distance of the system from the thermodynamic equilibrium and its temporal evolution. For sufficiently small perturbations necessary to assure linear responses such data is bound to remain undecisive as regards the spatial nature of the relaxation process, heterogeneous or homogeneous. The technique of solvation dynamics near the glass transition can probe the entire distribution of site specific energies and its approach towards equilibrium, so that apart from the mean solvation energy v(t) also higher moments in terms of the inhomogeneous optical linewidth σinh(t) become accessible. While v(t) maps the dielectric relaxation behaviour of the liquid, σinh(t) is found to be sensitive to the spatial nature of the underlying process. Contrasting experiment and simulation leads to the conclusion, that the relaxation time is a site specific quantity, i.e. the heterogeneous nature is found to dominate.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 455: Symposium T – Glasses and Glass Formers–Current Issues , 1996 , 127
Copyright
Copyright © Materials Research Society 1997

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References

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