Cu as an additive in the As0.4Se0.2Te0.4 glass: mean atomic volume and T-g

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.