Results of measurements of the mean atomic volume (V) and the glass transit
ion temperature (T-g,) for ten glass compositions of the As-Se-Te-Cu system
are reported and discussed. The compositions studied can be represented as
Cu-x(As0.4Se0.2Te0.4)(100-x),with the Cu content varying from 5 to 25 atom
ic percent (at.%.). In the V - x and T-g - x data, changes in slope are obs
erved at the composition with Cu content of 16.67 at.%. A model according t
o which, with progressive increase in the Cu content, CuAsSe2 and CuAsTe st
ructural units begin to form in place of some of the original As2Se3 and As
2Te3 structural units of the parent glass is able to account for the observ
ed changes in slope at a Cu content of 16.67 at.%. (C) 1999 Elsevier Scienc
e B.V. All rights reserved.