THE STRUCTURE OF ASXS100-X GLASSES STUDIED BY TEMPERATURE-MODULATED DIFFERENTIAL SCANNING CALORIMETRY AND RAMAN-SPECTROSCOPY

A novel temperature modulated differential scanning calorimetry (MDSC) technique has been applied to the measurement of the thermal properti es of AsxS100-x chalcogenide glasses in the glass transition region. A ll samples in this work have the same thermal history. The parameters glass transition temperature (T-g), relaxation enthalpy (Delta H), hea t capacity (C-p) and change of heat capacity (Delta C-p), which descri be the thermal events in the glass transition region, were measured. T he structurally determined parameters T-g, Delta H, C-p and Delta C-p have extrema when the composition of AsxS100-x glasses is As28.5S71.5 and As40S60. We show that AsxS100-x glasses where x < 25 at.% As are f ormed from two glass phases. From MDSC measurements, it was possible t o establish the probable composition of the high temperature glass pha se and, further, by using Raman spectroscopy, it was possible to corre late the MDSC results with the structure of the As-S glasses. (C) 1998 Elsevier Science B.V. All rights reserved.