Application of the Free Volume Concept to Glasses in the Ge-As-S System

• Published in: Glass physics and chemistry Vol. 28; no. 1; pp. 25 - 32
• Main Authors: Mel'nichenko, T N, Fedelesh, V I, Yurkin, I M, Mel'nichenko, T D
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer Nature B.V 01.01.2002
• Subjects: Bosons; Chalcogenides; Coordination numbers; Energy of formation; Fluctuation; Glass; Mathematical analysis; Modulus of elasticity; Spectrum analysis
• ISSN: 1087-6596; 1608-313X
• DOI: 10.1023/A:1014245312282

The energy of hole formation E^sub h^, the hole volume V^sub h^, and the fraction f^sub g^ of fluctuation free volume for glasses in the Ge-As-S system are calculated from the data on the elastic moduli, the microhardness H, and the glass transition temperature T^sub g^. It is shown that the fraction of fluctuation free volume in ternary glasses is considerably larger than that in arsenic chalcogenide glasses. For the glasses studied, the E^sub h^ energies fall in the range 13-18 kJ/mol and the hole volumes are equal to (7-84) × 10^sup -6^ m^sup 3^/mol. The concentration dependences of the elastic moduli and the parameters of the free volume theory for glasses in the As^sub 2^S^sub 3^-GeS^sub 2^ system are less pronounced than those for glasses in the As-S system with small coordination numbers of glass-former ions. This is explained by the topological transition observed in glasses of this system at a high germanium content. It is demonstrated that the parameters of the fluctuation free volume theory are related to the characteristics of the boson peak in the Raman spectra.[PUBLICATION ABSTRACT]