Differential thermal analysis studies have resulted in quantitative evaluation of the transformation kinetics of unstable glassy phases formed during cooling of solutions from equivalent isoplethal sections in the H 2O-NaCl-dimethyl-sulfoxide (DMSO) and H2O-NaCl-glycerol ternary systems. These ternary systems are of particular importance in the field of cryobiology, where knowledge of glassy phases may be especially crucial for long-term storage of biological materials at cryogenic temperatures. Activation energies for devitrification of glasses in both systems have been determined to be approximately 13 kcal/mole. The glasses were found to have approximately equal long-term stabilities. The DMSO-containing glasses appear to be more complex than glycerol-containing glasses because of the occurrence of a relatively high-temperature ternary eutectic reaction. The study of these systems appears to be a unique area for the cooperation of physical and biological scientists.