Structure and optical properties of glasses in the As-Se system

Subject of study. The properties of chalcogenide glasses in the As-Se system as members of a class of low-melting glasses that are transparent in the infrared spectral range were studied. Aim of the work. This work aimed to investigate the effect of the origin of the batch materials, the method of their preparation, and the synthesis temperature on the density, impurity absorption, and structure of the glasses in the As-Se system. Method. The glasses were synthesized by melting the batch in a temperature range of 600°C to 850°C. The synthesis was performed using different methods of batch preparation and arsenic and selenium obtained from several suppliers. The densities of the glasses were measured using a hydrostatic method. The optical absorption in the infrared spectral range was investigated using Fourier spectroscopy. Raman spectra were measured in the wavenumber range of 150–500 cm−1. Main results. The correlation of the structure and properties of glasses in the As-Se system was investigated at different synthesis temperatures and different modes of thermal processing of the batch. The properties of the glasses were established to be independent of the synthesis mode and the origin of the initial materials. Meanwhile, the preliminary thermal processing of the batch before sealing off the vial results in a significant reduction in the absorption owing to the oxygen impurities. The Raman spectra of the glasses containing 20–35 mol% of As demonstrate a broadening of the bands resulting from the mutual influence of the AsSe3/2 and SeSe2/2 structural units. The maximum concentration of the mixed structural units is observed at the ratio of the aforementioned structural units of 7:3. The glass structure can be described as a random distribution of the AsSe3/2 and SeSe2/2 structural units in the glass matrix. Practical significance. The investigated glasses can be applied in infrared optics to fabricate optical elements using hot molding.