The glass formation and crystallization of water-quenched GeSe2-GeTe-Sb2Te3, molten alloys was investigated by means of differential scanning calorinetry and X-ray diffraction. The glass forming region for a cooling rate of the order of 103 K/min was deduced. The effective activation energy of the crystallization process was obtained. All the results were analysed in the light of the current empirical parameters that characterize glass formation. It Is concluded that the best glass formers In that system are compositions of the type (GeSe2)73 (GeTe)15Sb2Te3)12. © 1988.