  Molecular dynamics in binary mixtures of water and glycerol was studied by
measuring the spectrum of water velocity auto-correlation in the frequency
range from 0.05 to 10 kHz by using the NMR method of modulated gradient spin
echo. The method shows that the diversity of diffusion signature in the short
spin trajectories provides information about heterogeneity of molecular motion
due to the motion in the micro-vortexes of hydrodynamic fluctuation, which is
especially pronounced for the mixtures with the low glycerol content. As
concentration of glycerol increases above 10vol%, a new feature of spectrum
appears due to interaction of water molecules with the clusters formed around
hydrophilic glycerol molecules. New spectrum exposes a rate thickening of
molecular friction, according to Einstein-Smoluchowski-Kubo formula, which
inhibits rapid molecular motions and creates the conditions for a slow process
of spontaneously folding of disordered poly-peptides into biologically active
protein molecules when immersed in such a mixture.
