Free-Volume Extended Defects in Structurally Modified Ge–Ga–S/Se Glasses

Herein, transformation of free-volume extended defects in selected chalcogenide glasses caused by thermal annealing for 10, 25, and 50 h is studied. For 80GeSe₂–20Ga₂Se₃ as well as for GeS₂–Ga₂S₃ glasses with different GeS₂ and Ga₂S₃ contents (80GeS₂–20Ga₂S₃, 82GeS₂–18Ga₂S₃, 84GeS₂–16Ga₂S₃), positron annihilation lifetime spectroscopy and Doppler broadening of annihilation radiation methods are applied. By analyzing the positron annihilation lifetime spectra decomposed into two components, it is shown that the observed changes in the second defect-related component for the 80GeSe₂–20Ga₂Se₃ glasses confirm the agglomeration of free volumes in the initial stage of annealing (10 h) with further fragmentation (25 h) and shrinkage (50 h). Increased content of Ge-related subsystem in the GeS₂–Ga₂S₃-based glasses results in the agglomeration of free-volume defects in the 82GeS₂–18Ga₂S₃ glasses with their further expansion in the 84GeS₂–16Ga₂S₃ matrix.