Reassessing the average bond energy of Ge-based chalcogenide glasses

The average bond energy ( A B E ) representing the energetical aspects of the amorphous covalent network structure has been utilized to explicate compositional dependence of properties such as glass transition temperature, hardness, and infrared transmission edge of chalcogenide glasses. Herein, we recognize that the existing formulations enabling calculation of A B E values can be further elaborated in order to better correlate the above-mentioned properties with A B E especially for the Ge-sufficient compositions. In this regard, we evaluate A B E values of ternary and quaternary selenide glasses exceeding 100 different compositions in a comparative way. It is now proposed that A B E values reflecting the number of bonds per atom result in an improved correlation with the properties. It is also pointed out that contributions of homopolar Ge-Ge bonds need to be more emphasized, since the fraction of which turns out to be correlated more conspicuously with the measured properties.