title: Structural signal of a dynamic glass transition.
abstract: Pentaphenyl trimethyl trisiloxane is an isotropic liquid at room temperature with a dynamic glass transition at 224 K. Using x-ray reflectivity, we see surface density oscillations (layers) develop below 285 K, similar to those seen in other metallic and dielectric liquids and in computer simulations. The layering threshold is approximately 0.23 times the liquid-gas critical temperature. Upon cooling further, there is a sharp increase at 224 K in the persistence of the surface layers into the bulk material, i.e., an apparently discontinuous change in static structure at the glass transition.
authors.affiliation: Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Sudeshna
authors.initials: S
authors.lastname: Chattopadhyay
authors.forename: Ahmet
authors.initials: A
authors.lastname: Uysal
authors.forename: Benjamin
authors.initials: B
authors.lastname: Stripe
authors.forename: Guennadi
authors.initials: G
authors.lastname: Evmenenko
authors.forename: Steven
authors.initials: S
authors.lastname: Ehrlich
authors.forename: Evguenia A
authors.initials: EA
authors.lastname: Karapetrova
authors.forename: Pulak
authors.initials: P
authors.lastname: Dutta