A study of the molecular motion in glucose/water mixtures using deuterium nuclear magnetic resonance

Using separate samples containing deuterated glucose and D2O, the motions o f the glucose and the water molecules in the viscous liquid and in the amor phous glass phase of glucose/water mixtures are examined. Spin-lattice rela xation measurements and spectra obtained in the solid confirm the existence of both a crystalline ice phase and an amorphous glass phase. Diffusion me asurements performed using the large gradient in the fringe field of a supe rconducting magnet determine the rates of translational motion of both the sugar and the water molecules over a limited range of temperature in the vi scous liquid region. From the deuterium nuclear magnetic resonance spin-lat tice relaxation time,T-1, the spin-spin relaxation time,T-2, and spin-align ment measurements, correlation times for the motion of these molecules are obtained. The correlation time for the alpha process increases dramatically at T-g, while the beta process continues into the low temperature glass ph ase, following an approximately Arrhenius relationship. (C) 1999 American I nstitute of Physics. [S0021-9606(99)51807-2].