M.K. Halimah

Optical Properties of Ternary TeO2-B2O3-ZnO Glass System

A series of ternary tellurite based glasses [(TeO2)70 (B203)30]100–x [ZnO]x glasses with different compositions of ZnO (x= 5 to 30 wt.% in steps of 5 wt.%) have been synthesized by melt quenching method. The role of ZnO to the glasses structure was studied by IR spectroscopy. FTIR spectra revealed broad, weak and strong absorption bands in the investigated range of wavenumber from 280–4000 cm−1 which associated with their corresponding bond modes of vibration and the glass structure. The indirect optical band gap and the direct optical band gap are in the range 2.08–3.12 and 1.54–2.36 eV, respectively. A decrease in the values of energy band gap Eg may come down to the reason that the non-bridging oxygen ion content increases with increasing ZnO content and shifting the band edge to lower energies. The optical band gap and Urbach energies were calculated from the absorption spectra measured between 190 and 900 nm at room temperature. The refractive index, n of the glasses change from 1.84–2.00 while the molar refractivities decrease from 13.06 to 12.00 with the increase of ZnO in mol%.

The Effect of Remelting on the Physical Properties of Borotellurite Glass Doped with Manganese

A systematic set of borotellurite glasses doped with manganese (1–x) [(B2O3)0.3(TeO2)0.7]-xMnO, with x = 0.1, 0.2, 0.3 and 0.4 mol%, were successfully synthesized by using a conventional melt and quench-casting technique. In this study, the remelting effect of the glass samples on their microstructure was investigated through density measurement and FT-IR spectra and evaluated by XRD techniques. Initial experimental results from XRD evaluation show that there are two distinct phases of glassy and crystallite microstructure due to the existence of peaks in the sample. The different physical behaviors of the studied glasses were closely related to the concentration of manganese in each phase. FTIR spectra revealed that the addition of manganese oxide contributes the transformation of TeO4 trigonal bipyramids with bridging oxygen (BO) to TeO3 trigonal pyramids with non-bridging oxygen (NBO).

Preparation and elastic moduli of germanate glass containing lead and bismuth.

This paper reports the rapid melt quenching technique preparation for the new family of bismuth-lead germanate glass (BPG) systems in the form of (GeO2)60–(PbO)40−x–(½Bi2O3)x where x = 0 to 40 mol%. Their densities with respect of Bi2O3 concentration were determined using Archimedes’ method with acetone as a floatation medium. The current experimental data are compared with those of bismuth lead borate (B2O3)20–(PbO)80−x–(Bi2O3)x. The elastic properties of BPG were studied using the ultrasonic pulse-echo technique where both longitudinal and transverse sound wave velocities have been measured in each glass samples at a frequency of 15 MHz and at room temperature. Experimental data shows that all the physical parameters of BPG including density and molar volume, both longitudinal and transverse velocities increase linearly with increasing of Bi2O3 content in the germanate glass network. Their elastic moduli such as longitudinal, shear and Young’s also increase linearly with addition of Bi2O3 but the bulk modulus did not. The Poisson’s ratio and fractal dimensionality are also found to vary linearly with the Bi2O3 concentration.

Infrared Study of Er3+/Yb3+ Co-Doped GeO2-PbO-Bi2O3 Glass

Heavy metal oxide glasses, containing bismuth and/or lead in their glass structure are new alternatives for rare eart (RE) doped hosts. Hence, the study of the structure of these vitreous systems is of great interest for science and technology. In this research work, GeO2-PbO-Bi2O3 glass host doped with Er3+/Yb3+ ions was synthesized by a conventional melt quenching method. The Fourier transform infrared (FTIR) results showed that PbO and Bi2O3 participate with PbO4 tetragonal pyramids and strongly distort BiO6 octahedral units in the glass network, which subsequently act as modifiers in glass structure. These results also confirmed the existence of both four and six coordination of germanium oxide in glass matrix.

Effect of AlF3 on the density and elastic properties of zinc tellurite glass systems

This paper presents the results of the physical and elastic properties of the ternary zinc oxyfluoro tellurite glass system. Systematic series of glasses (AlF3)x(ZnO)y(TeO2)z with x = 0–19, y = 0–20 and z = 80, 85, 90 mol% were synthesized by the conventional rapid melt quenching technique. The composition dependence of the physical, mainly density and molar volume, and elastic properties is discussed in term of the AlF3 modifiers addition that are expected to produce quite substantial changes in their physical properties. The absence of any crystalline peaks in the X-ray diffraction (XRD) patterns of the present glass samples indicates the amorphous nature. The addition of AlF3 lowered the values of the densities in ternary oxyfluorotellurite glass systems. The longitudinal and transverse ultrasonic waves propagated in each glass sample were measured using a MBS8020 ultrasonic data acquisition system. All the velocity data were taken at 5 MHz frequency and room temperature. The longitudinal modulus (L), shear modulus (G), Young’s modulus (E), bulk modulus (K) and Poisson’s ratio (σ) are obtained from both velocities data and their respective density. Experimental data shows the density and elastic moduli of each AlF3-ZnO-TeO2 series are found strongly depend upon the glass composition. The addition of AlF3 modifiers into the zinc tellurite causes substantial changes in their density, molar volume as well as their elastic properties.

Effect of Samarium Nanoparticles on Optical Properties of Zinc Borotellurite Glass System

The glass series of samarium nanoparticles (NPs) doped zinc borotellurite glasses were successfully fabricated by using conventional melt-quenching technique. The structural properties of the prepared glasses were investigated by X-ray diffraction (XRD) analysis and FTIR analysis. It was confirmed that the prepared glasses are amorphous in nature. The bonding parameters of the glasses were analyzed by using FTIR analysis and were found the formation of non-bridging oxygen. The density of these glasses were measured and found to be increased with increasing samarium NPs content. The optical absorption spectra of these glasses were revealed that the fundamental absorption edge shifts to higher wavelengths as the content of Sm2O3 (NPs) increases. The optical energy band gap are found to be decreased linearly with an increasing samarium NPs concentration which is due to the formation of non-bridging oxygen in the glass system.KeywordsBorotellurite glass; optical band gap, Samarium nanoparticles.

Elastic Properties of Thulium Doped Zinc Borotellurite Glass

A series of Tm-doped zinc borotellurite glass have been extracted by conventional melt-quenching method. The density was measured and it had been found that the value is increased by the increment of Tm3+ ion. The elastic properties of the sample were determined by measuring longitudinal and shear velocities using an ultrasound technique. Then the values inserted into equations that calculate the elastic moduli of the glass samples. These include longitudinal, shear, bulk, Young’s modulus and also the Poisson’s ratio. The longitudinal and shear velocities show an increment as Tm3+ increases from 0.01 to 0.03 mol content. The trend then changes as Tm3+ increases from 0.03 to 0.05 mol content. In terms of elastic moduli, it produces a rapid increment with Tm3+ until 0.03 mol content. But after that, the increment becomes slow until 0.05 mol of Tm3+. The value of Poisson’s ratio decreases with the addition of Tm3+ concentration.

Acoustic Evaluation of Hema Polymer Gel Dosimeter Phantoms

A new method for the evaluation of radiotherapy 3D polymer gel dosimeters has been developed using ultrasound to assess the significant structural changes that occur following irradiation of the dosimeters. Polymer gel dosimeters were being fabricated using a monomer named 2-Hydroxyl-Ethyl-Meta-Acrylate (HEMA) with the presence of gelatine as a gelling agent. The readymade gel which is the concentration for HEMA fixed at 2, 4 and 5% would then undergo an ultrasonic evaluation to test for the propagation of sound speed through it. In the observation of relationship between the ultrasound propagation speeds as the doses increase (focusing at the cross region from overlapped beams) and concentration of monomer, the propagation speed for all the three polymer gel dosimeter phantoms still varies between 1460 to 1570 m/s which is still in the range of speed of sound for human tissue [. The ultrasonic absorption attenuation coefficient dose sensitivity for polymer gel dosimeters for 2, 4 and 5% of monomer are in the range of 0.02 to 0.6 dB which is equivalent to human tissue. As a comparison, it can be seen that gel phantoms with high concentration of monomer (5%) is more sensitive to the radiation compared to the lower (2% and 4%) concentrations. Regarding the absolute results of mechanical and acoustic properties; the copolymer-in-oil phantom is equivalent with soft tissue.

Elastic Constants of (TeO2)90(AlF3)10−x(ZnO)x Zinc Oxyfluorotellurite Glasses

New series of ternary tellurite glasses in the form (TeO2)90(A1F3)90−x(ZnO)x have been successfully synthesized. Both longitudinal and shear ultrasonic velocities were measured in different compositions of the glass system by using the MBS8000 Ultrasonic Data Acquisition System at 10 MHz frequency and at room temperature. The elastic properties of ternary telluirte glasses (TeO2)90(A1F3)90−x(ZnO)x were measured as a function of composition. The ultrasonic velocity data, the density, the calculated elastic moduli and micro-hardness are composition dependent and discussed in terms of ZnO modifiers that were expected to change the physical properties of oxyfluotellurite glasses.

Structural, Thermal and Optical Studies of Bismuth Doped Multicomponent Tellurite Glass

In this communication, structural, thermal and optical absorption properties of bismuth doped multicomponent tellurite glass (69TeO2-10ZnO-10WO3-5Na2O-5TiO2-1.0Bi2O3 (mol %)) synthesized using melt quench method is reported. The X-ray diffraction confirms the amorphous structure of the synthesized glass. IR spectrum of bismuth doped glass show band at 601 cm-1. Raman analysis observed mainly in four spectral regions which are R1 (65-150) cm-1, R2 (280-550) cm-1, R3 (880-950) cm-1 and R4 (916-926) cm-1 and identified bands are assigned to respective molecular groups. Thermogravimetric analysis profile show stability regarding to weight loss. Differential scanning calorimetry indicates good thermal stability of the synthesized glass for its applications in optical fibers. The absorption spectrum identified the cutoff wavelength at 430 nm.