ملخص: The values of the apparent activation energy ([Delta]E), obtained from the variations of the glass transition temperature with heating rate, were investigated for different vitreous chalcogenide alloys. We observe, for vitreous Se, that [Delta]E is sensitive to the connectivity of the network (number of Se-8 rings). For binary alloys SeY (Y = As, Ge), for which the Y-atoms respect the 8 -- N rule, the variations of the normalized quantity [Delta]Esyst/[Delta]ESe with the average coordination number (m) allows the construction of a master curve ([Delta]Esyst/[Delta]ESe = -2.13m + 5.26). From this master curve, the value of m = 2.45, proposed by Phillips, is reached for [Delta]Esyst = 0. We also propose the use of this master curve to determine the value of the coordination number of added atoms (Y = Te), for which the 8 -- N rule seems not to be respected. We find a coordination number of Te included between 2.4 and 2.6, depending on the sample preparation.

لغة: إنجليزية