Eu3+ doped 1La2O3:2WO3:1B2O3 glass and glass-ceramic

In WO3-La2O3-B2O3 system, glasses were obtained in the region between 20 and 30 mol% La2O3. A liquid-phase separation region was observed near the WO3-B2O3 side. A glass with nominal composition 50WO3:25L2O3:25B2O3 doped with Eu2O3 was synthesized by melt quenching method. The obtained glass was characterized by X-ray diffraction (XRD), differential thermal analysis (DTA), UV-vis, infrared spectroscopy (IR) and photoluminescence spectroscopy (PL). According to the DTA data, Eu3+ ions decrease the glass transition temperature from 621 °C to 574 °C and crystallization temperature from 690 °C to 677 °C. Structural model for the glass network was suggested on the base of IR and UV-vis spectral investigations. It was established that WO4 and WO6 structural units (620-960 cm−1) and BO3 and BO4 polyhedra (1050-1380 cm−1) build up the glass network. During vitrification partial transformation of WO4 to WO6 and BO3 to BO4 was proved. The quenched glass is transparent in the visible region and exhibits typical absorption bands of Eu3+ ions due to the 4f transitions 5D0 → 7Fj (j = 0-4). A glass-ceramic consisting of LaBWO6:Eu3+ nanocrystals with enhanced photoluminescence emissions is synthesized. The intensity of emission increases drastically in the glass-crystalline sample compared with the glass and polycrystalline sample.