Incollection,
Large-scale structure in supercooled glycerol
Abstract Book of the XXIII IUPAP International Conference on Statistical Physics, Genova, Italy, (9-13 July 2007)
Abstract
Liquids that are cooled well below their melting point typically show an extraordinary increase in viscosity as the glass transition is approached. The static structure of a glass, however, is virtually identical to that of a liquid and it would therefore appear that there is no increasing static correlation length to accompany the glass transition. I will report on experiments studying heterogeneity in glycerol, a molecular glass-former. These experiments demonstrate the existence of an extended solid network dividing the fluid into separated, long-lived liquid pockets where the rotational diffusion of fluorescent probe molecules reveals markedly different local viscosities. The existence of such a network is further evidenced by bulk rheological measurements, that reveal the hallmarks of soft glassy rheology well above the glass transition: The network ages, has a yield stress, shear melts and shows history dependence. I will discuss some of the theoretical implications of these measurements for future work on fragile glass formers.
