Universal Scaling in the Aging of the Strong Glass Former SiO2

Publication Date

Summer 6-21-2016

Description

We show that the aging dynamics of a strong glass former displays a strikingly simple scaling behavior, connecting the average dynamics with its fluctuations, namely, the dynamical heteroge- neities. We perform molecular dynamics simulations of SiO 2 with van Beest-Kramer-van Santen interactions, quenching the system from high to low temperature, and study the evolution of the system as a function of the waiting time t w measured from the instant of the quench. We find that both the aging behavior of the dynamic susceptibility χ 4 and the aging behavior of the probability distribution P( f s,r ) of the local incoherent intermediate scattering function f s,r can be described by simple scaling forms in terms of the global incoherent intermediate scattering function C. The scaling forms are the same that have been found to describe the aging of several fragile glass formers and that, in the case of P( f s,r ), have been also predicted theoretically. A thorough study of the length scales involved highlights the importance of intermediate length scales. We also analyze directly the scaling dependence on particle type and on wavevector q and find that both the average and the fluctuations of the slow aging dynamics are controlled by a unique aging clock, which is not only independent of the wavevector q, but is also the same for O and Si atoms

Journal

Journal of Chemical Physics

Volume

144

First Page

234510-1

Last Page

234510-12

Department

Physics & Astronomy

Comments

JCP Editor's Choice. Invited Talk in JCP Editor's Choice Session at APS March Meeting 2017

DOI

10.1063/1.4953911

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