الفهرس 
Introduction and Literature SurveyOnly 14 pages are availabe for public view
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Abstract
Glasses of the composition 70%B2O3-(30-x)%Na2O-x%Y2O3 are manufactured by the melt quenching method. X-ray diffraction test indicate the amorphous structure of the glasses, with the presence of some YBO3 clusters in the high yttrium content samples. The FTIR analysis proved the presence of different borate groups and linkages. Forming ability of the glasses is found approximately stable for the low Y3+ content samples and increases for the heavily doped samples. Density of the samples is found to increase as the Y3+ concentration increases, while the molar volume decreases. The bond strength of the examined glasses suggests the covalent nature is dominant between bonds. All of the Y3+ doped glasses are found to emit greenish-cyan light when excited by λ_ex=365 nm. The photoluminescence intensity is shown to be enhanced by the generated YBO3 groups. The obtained correlated color temperature values with 82.5% purity recommend the suitability of these glasses for the applications in the outdoor illumination.
Electric conductivity, dielectric and magnetic properties have been also investigated. The ac conductivity (σac) and dielectric properties are investigated in the temperature range from 330 K to 530 K, and in the frequency range from100 Hz to 735 kHz. The dc conductivity (σdc) is found to increase from 3.7×10-11 to 1.6×10-5 S/m, with activation energy (ΔE) values lying between 0.52 and 1 eV. The ac conductivity was found to vary between 8.9 × 10-9 and 9.1 × 10-4 Sm-1, with a continuous nonlinear decrease of the frequency exponent (s) with increasing of the temperature. The experimental results are fairly fitted to the correlated barrier hopping (CBH) with density of pair sites varies around 2×1021 eV-1cm-3, and activation energy for relaxation (∆ER) proportionally increases with the increasing of Y2O3 in the glasses. Finally, addition of Y+3 ions to the sodium borate glass is found to convert the magnetic susceptibility from para- to dia-magnetic nature.