الفهرس 
Chapter I: Introduction & Literature SurveyOnly 14 pages are availabe for public view
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Abstract
This study is focused on the investigation of some physical properties of samarium and chromium doped lithium borate glass system . the study includes:
The preparation of samarium and chromium doped lithium borate glass system by conversional quenching melt technique . The prepared composition were
xSm2O3.[74.5B2O3.25Li2O.(0.5-x)Cr2O3]
Where, x=0,0.1, 0.2 0, 0.4 and 0.5 mol%,in order to study the effect of addition of Sm2O3 on the optical properties of the prepared samples by different experimental techniques . The amorphous nature of the prepared samples was confirmed by XRD. The variation of density as well as the molar volume with composition has been studied . The effect of Sm2O3 on the structure of the glass was investigated by IR spectroscopy indicating that, the addition of Sm2O3 leads to the presence of [BO3] and [BO4] structural units . However, the ratio N4 was found to depend on composition . No ESR signal was observed for chromium free sample indicating the absence of paramagnetic centers . The ESR parameters were calculated by using spin Hamiltonian . The spin- Hamiltonian parameters (g,A) confirm that Cr6+ ions are present in glass as Cr2- 4(VI) molecular ions in an octahedral site with a tetragonal compression . The increase in ^g/^g1 value with chromium content indicates that , the symmetry around Cr-ions are tetragonal distorted . Also the increase in the spin density with chromium content indicates the change in the valance state from Cr6+ to Cr3+ ions . Vis-NIR absorption spectra of the samples were obtained and analyzed . The oscillator strengths have been estimated . Judd-Ofelt approach has been applied for f-f transition.