الفهرس 
LITRATURE REVIEW AND OBJECTIVEOnly 14 pages are availabe for public view
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Abstract
Phosphate glasses doped with transitional metal (TM) ions, offer technological importance due to their acquired semiconducting properties, projected optical switching and photo-conducting characteristics. Vanadium-Lithium-Phosphate [V2O5-Li2O-P2O5] glass samples were prepared by the technique of melt-quenching. The following deductions are evoked from this study: 1. The effect of adding Li2O to the (S1) sample (with no V2O5), changed the structure of P2O5 from Q3 to Q2 as a response to the advent of a large number of (NBOs) due to the naturally expected bond breakage.
2. Upon introducing V2O5, it seems that the interaction of O2- ions tends to formV2O3 and VO2 as a direct result of reducing the positivity of vanadium molecules. This deduction is supported by the FTIR results. The V2O3 and VO2 stimulate vanadium to act as a modifier, i.e. they occupy interstitial positions in the phosphate matrix, thus producing NBOs.
3. The amorphous nature of these glasses was verified through XRD examination at room temperature.
4. The calculated density of samples increased from 2.373 − 2.391 g/cm3 as the V2O5 content was increased.
5. Upon doping with various V2O5 concentrations, linear and non-linear optical parameters indicated an anomalous behavior of the samples. Thus dispersion parameters could be controlled by the doping concentration of V2O5.6. The glass sample (S1), doped with 0.2 % (V2O5), exhibits reduced values of (Ed) and (n∞). In addition, it shows lower values of: reflection loss, mean dispersion, dispersive power, molar refractivity and polarizability, as well as non-linear optical parameters , the 3rd order susceptibility and the non-linear refractive index coefficient.
7. The glass sample (S2), similarly doped with 0.4 % (V2O5), shows lower values of (Eog), indicating that the covalent bonding nature decreases with increasing the concentration of V2O5.
8. from UV results, the glass composition leads to a range of colors depending on the alkali oxide content. The distorted octahedral coordination with O2 forms the trivalent greenish vanadium ions due to the (3d2) state. Moreover, the tetravalent bluish vanadium ions exist as a result of (3d1) transition characteristics. The visual appearance of the greenish color, which deepens with the increase of (V2O5) content, supports the presence of (V3+) ions. Consequently, due to the formation of NBO sites, the vanadium ions V+5 were able to find possible oxygen ions that induced them to get involved in the redox mechanism, thus producing V4+ and V3+.
9. The free volume nanostructure has been studied by PAL. At low doping concentration of V2O5 (0-0.4 mol %) a maximum value of 2.05ns is obtained for τ3 which corresponds to a free volume of 101.3A°3 due to depolymerization of the phosphate network. This constituted an explanation for the increase in I2 from 59.% to 73.9% and a decrease in τ2 due to increase in NBOs. At high doping concentration of V2O5 (1-2 mol %) the free volume is found to decrease to 24.3 A°3 along with an increase in I3 from 0.7% to 9%. This has been explained the increase of V3+ and V4+ ions in agreement with FTIR results where the vanadium oxide acts as a modifier.10. Furthermore, the deductions from PL and PAL diagrams support the FTIR and UV interpretations, in that the V2O5 strips off the released electrons in the glass samples; thus converting V2O5 into V2O3 and VO2. In this regard, optical detection and solar energy conversion provide the most favorable candidates as contemporary applications.
11. The above deduced inferences find contemporary applications based on the phenomena of non-linearity in modified glass matrices, namely; laser glass with low nonlinear refractive index as well as optical switching with high refractive index.
For future work, more investigations in advanced plasma techniques on phosphate glasses could steer and administer unprecedented purposes, specifically in nuclear reactors and outer space transportation.