ENTHALPY RELAXATION IN GEXSE1-X CHALCOGENIDE GLASSES

Enthalpy relaxation in selenium samples and GexSe1-x alloys with x=0.0 8 and 0.12 has been investigated by differential scanning calorimetry. All the samples have been submitted to comparable aging temperatures 10 degrees C below the glass transition temperature for a period from 0.5 to 800 h. The apparent activation energy and the Narayanaswamy par ameter, X, were calculated and the non-exponentiality parameter, beta, was estimated for the samples. The introduction of the germanium atom s in the selenium chain changes the distribution of relaxation times, increases the relaxation rate per decade and decreases the apparent ac tivation energy. No differences were observed in the GexSe1-x alloys i n the evaluation of these parameters. (C) 1998 Published by Elsevier S cience B.V. All rights reserved.