NATURE OF THE RELAXATION PROCESSES IN THE SUPERCOOLED LIQUID AND GLASSY STATES OF SOME CARBOHYDRATES

Dielectric relaxation measurements are made in a number of carbohydrates in their supercooled liquid and glassy states over a frequency range 10(6)-10(-3) Hz and a temperature range 77-400 K. Differential scanning calorimetric measurements are also made. In all the samples two relaxations, which were identified as alpha-and beta-relaxations, were observed. The cc-relaxation is very broad and is strictly non-Arrhenius, and it follows a critical power-law temperature dependence. The beta-process is Arrhenius, with an activation energy varying. from 8.5 to 13 kcal/mol. Also a systematic variation of the magnitude of the beta-process with the molecular structure is noted. The origin of the beta-process in these systems appears to be intramolecular in nature.