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Nominal glass compositions x mol%(Li 2 O) (30-x) mol%(Na 2 O) 65mol%(B 2 O 3): 5mol%(Sm 2 O 3) 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 (E g), Urbach energy tail (∆E), linear refractive index (n 0), nonlinear refractive index (n 2), linear optical susceptibility χ (1) and the third order of non-linear optical susceptibility χ (3) have been calculated before and after 8MRad γirradiation. The analysis of the absorption coefficient data revealed the existence of an allowed indirect transition both before and after γirradiation. It was observed that the value of optical energy gap depends on the value of lithium content (x). E g increases from (3.15eV-3.3eV) and from(2.93 eV-3.09eV) before and after γirradiation 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 E g. It was found that n 0 , χ (1) , n 2 and χ (3) vary from (2.32-2.35), (0.35-0.363)esu., (24.1-27.71)x10-12 &(1.48-1.73)x10-12 esu.when lithium content value varies from 0 to 30 mol% before γirradiation respectively. The parameters n 0 , χ (1) , n 2 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)x10-12 esu.afterγ-irradiation respectively. The variation in optical band gap and Urbach energy are due to the variation in the glass structure.