Glass formation in the MoO3–Nd2O3–La2O3–B2O3 system

Abstract In MoO 3 –Nd 2 O 3 –B 2 O 3 and MoO 3 –Nd 2 O 3 –La 2 O 3 –B 2 O 3 systems, glasses were obtained in the region between 20 and 30 mol% Ln 2 O 3 . A liquid-phase separation region was observed near the MoO 3 –B 2 O 3 side up to 20 mol% Ln 2 O 3 (La, Nd). The amorphous phases were characterized by X-ray diffraction (XRD), differential thermal analysis (DTA), UV–VIS and infrared spectroscopy (IR). According to DTA data B 2 O 3 -rich glasses are stable up to 630 °C while glasses rich in MoO 3 are stable up to 430 °C. The glasses are transparent in the visible region. Structural models for the glasses network were suggested on the basis of IR spectral investigations. It was established that BO 3 (1380 cm −1 ), BO 4 (1100–950 cm −1 ) and MoO 4 (860 cm −1 ) groups build up the glass network. MoO 6 units (band at 880 cm −1 ) together with BO 3 units participate in the formation of the glass network with a high MoO 3 content (80–90 mol%).