HETEROGENEITY AT THE GLASS-TRANSITION - TRANSLATIONAL AND ROTATIONAL SELF-DIFFUSION

Self-diffusion coefficients, D, have been measured in the glass formin g liquids salol, glycerol, phenolphthaleine dimethyl ether (PDE), cres olphthaleine dimethyl ether (CDE), and alpha alpha alpha-trinaphthylbe nzene (TNB) In the supercooled regime. The NMR static magnetic field g radient technique was applied where D > 10(-14) m(2) s(-1) can be atta ined. 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 h eterogeneity are related to a phenomenological environmental fluctuati on model in view of recent diffusion and relaxation data close to the glass transition.