Structure–property correlations in the SiO2–PbO–Bi2O3 glasses

Abstract

SiO 2 -PbO-Bi 2 O 3 glasses having the composition of 35SiO 2 -xPbO-(65-x)Bi 2 O 3 (where x = 5, 10, 15, 20, 25, 35, 45; in mol%) have been prepared using the conventional melting and annealing method. Density, molar volume and Vickers microhardness of the prepared glasses were measured. Infrared (IR) and UV-visible spectroscopic techniques were used for structural studies of these glasses. Density as well as the microhardness increase systematically and, conversely, the molar volume decreases with increasing the lead oxide content. This behavior can be explained by the correlation with the glass structure. Increasing the lead oxide content (C20 mol%) increases the network former PbO 4 groups which can play an important role in increasing the connectivity and compactness of the glass matrix via increasing the cross-linking with the other constituent silicate and bismuthate structural units. The increased compactness may explain, in turn, the increase of the density and microhardness. IR spectra reinforce the idea that bismuth participates in the glassy network predominantly as BiO 6 octahedral structural units. UV-VIS optical absorption spectra revealed UV-charge transfer absorption bands related to the contribution of Pb 2? ions in the region 350-385 nm; in addition to the extrinsic absorption of trace iron impurities in the range 220-290 nm. In the visible region, three optical bands in the ranges 415-435, 605-650 and 880-890 nm were correlated with the contribution of electronic transitions in Bi 3? ions. Calculation of the optical mobility gap and the width of the energy tail of glass from the UV-VIS absorption indicated a slight increase followed by a decrease in their values. The behavior change occurred at the glass in which PbO content is 20 mol% where lead oxide starts to participate into the glassy matrix as a network former. The combination of analytical FTIR and UVvisible spectroscopy provided a consistent picture of structure-property relations in this glass system.

Sol–gel synthesis, paramagnetism, photoluminescence and optical properties of Gd-doped and Bi–Gd-codoped hybrid organo-silica glasses

“…[2,14,20,[26][27][28][29][30]. The shoulder located at 1,024 cm -1 , which appears only in the spectrum of Bi-Gdcodoped glass, is ascribed to the Bi-O bond in the BiO 3 structural units [31,32]. The shoulders at 538 cm -1 can be assigned to the metal-oxide (Gd-O) stretching vibration [10].…”

“…m = 1/2 for allowed direct transition, m = 3/2 for forbidden direct transition, m = 3 for forbidden indirect transition and m = 2 refers to indirect allowed transitions [6,20,31,35,[37][38][39][40]. Using Eq.…”

Investigation and properties of novel low melting glasses in the ternary system Sb2O3–PbO–Me2O3

“…Then this PbO 4 group can enter the vitreous network. Indeed, there are numerous examples of glass compositions with a very large content of lead oxide 35–39,45 . In the Sb 2 O 3 –PbO binary system, there are two different glass domains, the first one for large Sb 2 O 3 concentrations and the second one when lead is predominant.…”

“…Indeed, there are numerous examples of glass compositions with a very large content of lead oxide. [35][36][37][38][39]45 In the Sb 2 O 3 -PbO binary system, there are two different glass domains, the first one for large Sb 2 O 3 concentrations and the second one when lead is predominant. Not surprisingly characteristic temperatures reflect this situation (Figure 6): less stable glasses are found in the intermediate composition range.…”

“Gamma Rays Interactions on Optical, FTIR and ESR Spectra of Alkaline Earth Binary Borate Glasses”

“…According to Feifei et al [23],the increasing in glass bond strengthorigins a larger splitting between the two energetic bands (valence and conduction)leading toa growing in the value of optical band gap. This concept is approvedbyAbo-Naf et al [24] who supposed that, the more covalent bonds inside the glassy network, not only strengthens its structure but also increasesthe bridging oxygens numbersthen higher Eopt values are obtained. However, irradiating glasses causes the alteration in their oxygen bond strength thru increasing the NBO concentration,becauseoxygens displacements from their normal positions lead to the transformation of the bridging oxygens BO into the non-bridging oxygens NBO.…”