Structure and properties of low-phonon antimony glasses and nano glass-ceramics in K2O–B2O3–Sb2O3 system

A series of new low-phonon and low softening point monolithic antimony glasses and nano glass-ceramics (crystallite diameter 7–16 nm) containing as high as 90 mol% Sb2O3 were prepared in the ternary K2O–B2O3–Sb2O3 (KBS) system. Infrared spectra and X-ray analysis establish that their structures closely resemble valentinite form of Sb2O3. The phonon energy has been found to be 592–602 cm−1. The softening point (Ts), glass transition temperature (Tg), coefficient of thermal expansion (CTE), dielectric constant (ε) and optical band gap (Eopt) have been found to vary in the ranges 331–392 °C, 234–264 °C, 201–222 × 10−7 K−1, 12.4–14.5 and 3.15–3.22 eV, respectively. These properties are found to be controlled by the covalent character and optical basicity of prepared samples. The average electronic polarizability of the oxide ions and optical basicity are found to increase while interaction parameter and metallization criterion decrease with increase in Sb2O3 content.