Fig. 1

Phase transformations upon cooling and heating. a Selected cooling curves from the melt measured at various rates. Crystallization occurs at slow cooling up to approximately 200 K s⁻¹. At faster cooling the sample forms a glass. b Heating curves measured at 1000 K s⁻¹ after cooling at various rates between 0.1 K s⁻¹ and 40,000 K s⁻¹. The previous cooling rates are indicated only for the thickly drawn curves, while curves measured for other cooling rates are thin and gray-colored