In contrast with the usual assumption that proton spin relaxation in glycerol originates from rotational molecular diffusion, quantitative evaluation of the temperature and Larmor frequency dependence in the ranges −30 °C to+70 °C and 10 kHz to 120 MHz, respectively, gives extensive agreement with Fick's translational random walk model. This observation is supported by direct measurements of the self-diffusion constant by means of the pulse gradient method, which reveals the same activation barrier as relaxation spectroscopy.

Abstract Proton nuclear magnetic relaxation times in pure glycerol and glycerol water mixtures have been measured in the frequency range from 450 kHz . . . 120 MHz from -20 °C .. . 70 °C. The results cannot be interpreted in terms of the well-known distributions of dielectric correlation times (Log-Gaussian, Cole-Davidson etc.), as has been proposed recently. Instead a new type of distribution function, called "diffusion-distribution", is introduced.