6533b82cfe1ef96bd128f416

RESEARCH PRODUCT

Heterogeneity at the Glass Transition:  Translational and Rotational Self-Diffusion

Hans SillescuInyong Chang And

subject

Self-diffusionDiffusionRelaxation (NMR)Rotational diffusionThermodynamicsMagnetostaticsSurfaces Coatings and FilmsCondensed Matter::Soft Condensed Matterchemistry.chemical_compoundNuclear magnetic resonancechemistryMaterials ChemistryDimethyl etherPhysical and Theoretical ChemistrySupercoolingGlass transition

description

Self-diffusion coefficients, D, have been measured in the glass forming liquids salol, glycerol, phenolphthaleine dimethyl ether (PDE), cresolphthaleine dimethyl ether (CDE), and ααβ-trinaphthylbenzene (TNB) in the supercooled regime. The NMR static magnetic field gradient technique was applied where D >10-14 m2 s-1 can be attained. The results are similar to previous diffusion experiments where an enhancement of translational diffusion was found in comparison with rotational diffusion and shear viscosity. Various models of spatial heterogeneity are related to a phenomenological environmental fluctuation model in view of recent diffusion and relaxation data close to the glass transition.

https://doi.org/10.1021/jp9640989