Preparation and characterization of heavy-metal oxide glasses: Bi2O3–PbO–B2O3–GeO2 system

Abstract

High-refractive-index glasses of heavy-metal oxides have large optical non-linearities which make them promising for optoelectronic applications. This paper describes the fabrication and characterization of the xBi₂O₃–PbO–B₂O₃–(52–x)GeO₂(BPBG) glass system with x= 10, 15, 20, 30 and 35. The BPBG glasses were melted in a high-purity alumina crucible placed in a Super Khantal resistance furnace at 1000 °C for 30 min and then poured onto a steel plate. The characterization was done by X-ray diffraction (XRD), density, dilatometry, light absorption (UV–VIS–IR) and linear refractive-index measurements. The infrared spectra show the presence of BiO₆ and GeO₆ in the glass structure suggesting a network former role for the bismuth oxide. These measurements allowed us to estimate the non-linear refractive index n₂, using Line's formula, to be as high as 1.5 × 10^–18 m² W^–1.