Influência dos íons alcalinos nos comportamentos térmico e óptico de vidros germanatos de nióbio

Abstract

New glasses of ternary composition GeO2-Nb2O5-M2O were prepared and characterized in which M = Li, Na, K, Rb, Cs, where germanium oxide acts as a vitreous former, niobium oxide acts as an intermediate and metal oxide alkaline acts as a network modifier. Modifiers are added due to the high melting point of the niobium oxide (Tf = 1512 ° C) and germanium oxide (Tf = 1115 ºC) to decrease the melting point and viscosity. The initial blends were melted in platinum crucible in a high temperature furnace and quenched. Thermal treatments were applied to the glasses prepared for a study on precipitated phases in each sample. Structural studies were analyzed by Raman spectroscopy, differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The optical characterizations were performed by spectroscopy in the ultraviolet, visible and near infrared region and FTIR spectroscopy. Studies were carried out on the luminescent properties of glasses of the original matrix doped with 0.3 mol% of Europium Oxide used as a structural probe, as well to analyze the influence of the modifiers on the emissions, lifetime and quantum efficiency.