The maximum of glass-forming ability in Se-GeSe2 system - Phillips-Thorpe threshold and/or eutectic?

Glass-forming ability of Ge0.08Se0.92 (eutectic composition) and Ge0.20Se0.80 (Phillips-Thorpe threshold where the mean coordination number equals to 2.4) are compared employing very slow melts cooling. Using X-ray diffraction the presence of crystalline phase (Ge4Se9) was found in slowly cooled melt of Ge0.20Se0.80. It is suggested that in Se-GeSe2 system the maximum of glass-forming ability is shifted to the vicinity of the eutectic composition.