6533b861fe1ef96bd12c5710
RESEARCH PRODUCT
2 H-NMR-Stimulated Echo Study of Ultraslow Reorientational Motion in Viscous Glycerol near Its Glass Transition Temperature
R. M. DiehlF. FujaraHans Sillescusubject
Materials scienceCondensed matter physicsRelaxation (NMR)Turn (geometry)JumpGeneral Physics and AstronomyRotational diffusionRotational temperatureGlass transitionMolecular physicsRotational correlation timePulse (physics)description
2H-NMR stimulated echo experiments have been performed in order to study the molecular basis of the ?-process in viscous glycerol near its glass transition temperature. Decay functions following modified Jeener-Broekaert pulse sequences were compared with predictions from different models for molecular reorientation. Rotational diffusion, rotational random jumps, rotational fixed-angle jumps and combinations of diffusive and jump motions have been tested. All data are fitted with a log-Gaussian distribution of correlation times. Thereby, small-but finite-angle reorientation processes turn out to dominate in the 10-3 s.. 100 s regime. Pure large-angle rotational jumps can be ruled out with high significance. The mean rotational correlation time, ?c, agrees with results from other relaxation experiments which monitor the ?-process of the glass transition.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 1990-10-01 | Europhysics Letters (EPL) |