TEMPERATURE AND VISCOSITY FOR STRUCTURAL COLLAPSE AND CRYSTALLIZATIONOF AMORPHOUS CARBOHYDRATE SOLUTIONS

Temperatures and bulk viscosities, at which certain changes in the phy sical state take place, were examined in various amorphous, supersatur ated carbohydrate solutions. The glass transition temperature (Ts) of these aqueous sugar glasses ranged from 181 K to 381 K. Temperatures o f physical state changes, such as glass-softening, structural collapse , water and solute crystallization, are quite predictable. They are pr imarily dependent on the Tg (less or little dependent on the type of c arbohydrates), and occur consistently at certain temperatures above th e Tg. Bulk viscosities of amorphous carbohydrate solutions, at which t he structural collapse, glass-softening, devitrification and solute cr ystallization take place, are predicted to be of the order of 10(8-11) , 10(7-10), 10(5-7) and 10(3-6) pa s, respectively. These values may a lso serve as reference points for other amorphous systems.