I. Kashif

Optical properties of Lead bismuth borate glasses doped with neodymium oxide

Neodymium doped Lead bismuth borate glasses with the composition of 25PbO-25Bi2O3-50B2O3:xNd2O3, where x=0.5, 1, 1.5 and 2 mol%, have been prepared by melt quenching technique. The behavior of the density and molar volume allows concluding that, addition of Nd2O3 leads to the formation of non-bridging oxygen. Rare earth ion parameters have been calculated and studied. The optical band gap (Eg), and band tails (Ee) were determined. Judd-Ofelt theory for the intensity analysis of induced electric dipole transitions has been applied to the measured oscillator strengths of the absorption bands to determine the three phenomenological intensity parameters Ω2, Ω4 and Ω6 for glass. It was observed that the deviation parameters, rms, was found to be 0.56:0.58(×10(-6)). The estimated Judd-Ofelt parameters were found to be Nd2O3concentration dependent. The hypersensitive transition, (4)I9/2→(4)G5/2+(2)G7/2, is closely related to Ω2 parameter.

XRD and FTIR studies the effect of heat treatment and doping the transition metal oxide on LiNbO3 and LiNb3O8 nano-crystallite phases in lithium borate glass system.

Glasses of various compositions in the system 90 Li2B4O7-10 Nb2O5 mixed with T.M ions (where T.M is the transition metal) were prepared by quenching technique. Heat-treatment of the parent glasses was performed at 540, 570 and 620 °C, for 5 and 16 h. The glass structure evolution during the controlled crystallization was examined by XRD and FT-IR spectroscopy analysis. The crystalline phases present in the glass ceramics were identified via X-ray diffraction as a function of heat treatment. The FT-IR data propose for these glasses and heat-treated glass network structures mainly built by: di-, tri-, tetra-, penta-and ortho-borate groups. It was found that the quantitative evolution of these various borate species in the glass structures is influenced by the transition metal. A detailed discussion relating to the N4 evolution with the T.M content was made.

Elucidation of the crystallization kinetics for sodium-alumino-silicate glasses containing different amounts of manganese oxide

The glass samples [40SiO2 + 5Al2O3 + {55 − x}Na2O + xMnO2] where x = 0.05, 0.2, 0.4, 0.6, 0.8, and 1 mol% MnO2 before and after being heat treated were subjected to X-ray diffraction. The diffraction lines provided clear evidence of the nucleation and growth, which are characteristic of sodium silicate phase. Crystallization studies were conducted using differential thermal analysis. Crystallization peak temperatures were identified and the transformed fractions were determined. Both the rate of growth, K 0, and the activation energy, E, depend on the influence of manganese ions in the glass network as a modifier or as a former and the manganese content. The values of the Avrami parameter, n, were calculated using two methods and were in excellent agreement. The process of nucleation and growth rate depends on the manganese content.

Influence of heat treatment on structure and some physical properties of lithium boro-niobate glass

The glass composition (90 mol% Li2B4O7–10 mol% Nb2O5) was prepared by the melt quenching technique. The quenched sample was heat treated at 480°C, 545°C and 630°C for 5 h and heat treated at 780°C with different time. The times were 5, 10, 15, 20, 28, and 36 h. The glass and glass ceramics were studied by differential thermal analysis (DTA), X-ray diffraction (XRD), and dc conductivity as a function of temperature. Lithium niobate (LiNbO3) and lithium diborate (Li2B4O7) were the main phases in glass ceramic addition to traces from LiNb3O8. Crystallite size of the main phases determined from the X-ray diffraction peaks are in the range <100 nm. The fraction of crystalline (LiNbO3) phase increases with increase the heat treatment temperature and time. The relation between physical properties and structure were studied.

Glass formation in the system Li2B4O7–Pb3O4–CuO using X-ray diffraction

X-ray diffraction was performed to construct the phase diagram for the ternary Li2B4O7–Pb3O4–CuO glass system. Three principal regions were identified: (1) a glass-forming region observed at the composition (75 < Li2B4O7 < 100) mol%, (0 < CuO < 35) mol% and (0 < Pb3O4 < 70) mol% in the ternary system, and (100 − x) mol% Li2B4O7–x mol% Pb3O4 where x = 0 up to 70, (100 − y) mol% Li2B4O7–y mol% CuO where y = 0 up to 25 in the binary system;. (2) a crystalline region: all compositions prepared from the binary system Pb3O4–CuO and the ternary system containing Li2B4O7 up to 60 mol%; (3) a partially crystalline region formed between the glass and crystalline regions.