Chalcogenide Glasses. Part 4. Crystallization and Glass Transition Characteristics in AS(2-x)Sb(x)S(3) Glass-Forming System.
Final rept. 1 Nov 83-31 Mar 86,
AIR FORCE WRIGHT AERONAUTICAL LABS WRIGHT-PATTERSON AFB OH
Pagination or Media Count:
The crystallization characteristics of As2xSbxS3 chalcogenide glasses with nominal compositions ranging from x0.0 to 2.0 in a melt quenched bulk form and a thin film form were studied, and a self-consistent model of crystallization mechanism was developed. Scanning electron microscopy and X-ray diffraction analysis were used to examine the microstructure and phases present as a function of composition. Differential scanning calorimetry, both in isothermal and dynamic mode, was utilized to determine the kinetic parameters, glass forming tendency, and glass transition characteristics as a function of composition. All results for the melt quenched bulk glasses were consistent with the proposed model in which 1 the glasses exhibit two phase heterogeneity consisting of Sb2S3 phase and As2S3 matrix phase, 2 the nucleation sites are at the surface of the bulk in the Sb2S3 phase, and 3 the Sb2S3 crystals grow in the glassy As2S3 matrix by diffusion of antimony atoms through As2S3 phase, and subsequent inter-connection of Sb2S3 phase. The experimental results with the vapor deposited film samples suggested a slightly different model, in which no heterogeneity existed in the as-deposited state.