title: Temperature-dependent two-state dynamics of individual cooperatively rearranging regions on a glass surface.
abstract: Cooperatively rearranging regions (CRRs) play a central role in the temperature dependence of glass dynamics. We record real-time atomic resolution movies of individual CRRs, while ramping their temperature. Between 295 and 326 K, well below the bulk glass transition temperature T(g), the rate coefficient for two-state hopping of CRRs increases over tenfold, yielding an Arrhenius activation barrier of ≈10k(B)T(g). By time resolving the dynamics of many individual CRRs, we show that highly stretched dynamics of the CRR ensemble results mainly from spatial heterogeneity, less from temporal heterogeneity of individual CRRs.
authors.affiliation: Beckman Institute for Advanced Science and Technology, University of Illinois, Urbana, Illinois 61801, USA.
authors.forename: S
authors.initials: S
authors.lastname: Ashtekar
authors.forename: J
authors.initials: J
authors.lastname: Lyding
authors.forename: M
authors.initials: M
authors.lastname: Gruebele