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

Abstract In WO 3 –La 2 O 3 –B 2 O 3 system, glasses were obtained in the region between 20 and 30 mol% La 2 O 3 . A liquid-phase separation region was observed near the WO 3 –B 2 O 3 side. A glass with nominal composition 50WO 3 :25L 2 O 3 :25B 2 O 3 doped with Eu 2 O 3 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, Eu 3+ 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 WO 4 and WO 6 structural units (620–960 cm −1 ) and BO 3 and BO 4 polyhedra (1050–1380 cm −1 ) build up the glass network. During vitrification partial transformation of WO 4 to WO 6 and BO 3 to BO 4 was proved. The quenched glass is transparent in the visible region and exhibits typical absorption bands of Eu 3+ ions due to the 4 f transitions 5 D 0 → 7 F j ( j = 0–4). A glass–ceramic consisting of LaBWO 6 :Eu 3+ 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.