Glass formation and structure of glasses in B2O3―Bi2O3―MoO3 system

The purpose of this paper is to study the glass formation tendency in the ternary system B2O3―Bi2O3―MoO3 and to define the main structural units building the amorphous network. A wide glass formation area was determined which is situated near the Bi2O3―B2O3 side. A liquid phase separation region was observed near the MoO3―B2O3 side for compositions containing below 25 mol% Bi2O3 and their microheterogeneous structure was observed by SEM. The phase formation was characterized by X-ray diffraction (XRD). By DTA was established the glass transition temperature (Tg) in the range of 380–420 °C and crystallization temperature (Tx) vary between 420 and 540 °C. The main building units forming the amorphous network are BO3 (1270 and 1200 cm− 1), BO4 (930–880, 1050–1040 cm− 1), MoO4 (840–760 cm− 1) and BiO6 (470 cm− 1). It was proved that Bi2O3 favors the BO3 → BO4 transformations while MoO3 preserves BO3 units in the amorphous network.

Research Highlights
► Glass formation and structure of glasses in B2O3―Bi2O3―MoO3 system.
► The MoO4, BiO6, BO3 and BO4 units exist in the amorphous network.
► Bi2O3 favors the BO3→BO4 transition, while MoO3 preserves the BO3 units in the amorphous network.
► The liquid phase separation covers a wide region of compositions.