Document Type : Original Article
Authors
1
College of Women for Arts, Science and Education, Physics Department, Ain Shams University
2
2 Physics Division, Spectroscopy Department, National Research Centre, 33 El‑Behouth St., Dokki, Cairo 12622,Egyp
3
Physics Division, Electron Microscope and Thin Films Department, National Research Centre,33 El‑Behouth St., Dokki, Cairo 12622, Egypt
Abstract
Nominal glass compositions x mol%(Li2O) (30-x) mol%(Na2O) 65mol%(B2O3): 5mol%(Sm2O3) where x=(0, 10, 20 and 30) mol% have been prepared by the conventional quenching melt annealing technique. The optical constants (α, n, k), optical energy gap (Eg), Urbach energy tail (∆E), linear refractive index (n0), nonlinear refractive index (n2), linear optical susceptibility χ(1) and the third order of non- linear optical susceptibility χ(3) have been calculated before and after 8MRad γ- irradiation. The analysis of the absorption coefficient data revealed the existence of an allowed indirect transition both before and after γ- irradiation. It was observed that the value of optical energy gap depends on the value of lithium content (x). Eg increases from (3.15eV- 3.3eV) and from(2.93 eV -3.09eV) before and after γ- irradiation respectively when lithium content value (x) varies from 0 to 20 mol% then decreases to 3.24eV and 2.85 eV at 30 mol% of lithium content before and after γ-irradiation respectively. ΔE decreases from 0.1193 eV to 0.095 eV and from 0.565 eV to 0.401 eV with increasing lithium content from 0 to 20 mol%, then increases to 0.114 eV, 0.512 eV at 30 mol% of lithium oxide respectively before and after gamma irradiation. The linear and nonlinear optical parameters have been estimated from the obtained values of n and Eg. It was found that n0, χ(1), n2 and χ(3) vary from (2.32-2.35), (0.35- 0.363)esu., (24.1-27.71)x10-12&(1.48-1.73)x10-12esu.when lithium content value varies from 0 to 30 mol% before γ-irradiation respectively. The parameters n0, χ(1), n2 and χ(3) are found to vary from (2.37-2.63), (0.368-0.473), (29.332-71.626)x10-12& (1.846-5.001)x10-12esu.afterγ-irradiation respectively. The variation in optical band gap and Urbach energy are due to the variation in the glass structure.
Keywords
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