CRYSTALLIZATION BEHAVIOR DETERMINED BY DTA METHOD OF GLASS-FORMING MELTS IN THE CaO-Ga//2O//3-GeO//2 SYSTEM.

The temperatures of glass transition (T//g), crystallization (T//c) and melting (T//m) during heating were measured for compositions of 50-70 CaO multiplied by (times) 15-40 Ga//2O//3 multiplied by (times) 0-20 GeO//2. The crystallization temperature (T//k) during cooling and the fraction of precipitated crystals were measured from DTA data. Time-temperature-transformation (T-T-T) curves were determined experimentally. A cooling rate (Q)-temperature-transformation (X) (Q-T-T) curve is obtainable by plotting minus Q**n multiplied by (times) ln(1 minus X) vs. temperture, where n depends on crystallization mechanism and other factors and is 4 and 1 or 2 above and below 1150 degree C, respectively.