Vanadium oxideV₂O₃ thin films were synthesized by sol-gel spin coating method and investigated by XRD, FE-SEM, EDAX, and UV-Vis- NIR spectroscopies. XRD and EDAX analysis has confirmed that the initial powdered orthorhombic V₂O₅ compound dissolved in H₂O₂ solution, heat treated at ≈ 700  and spin coated has been transformed into monoclinic V₂O₃- phase thin films, resulting in free V³⁺ ion Formation. The morphology and optical analysis of the obtained films revealed that the grain size increases and the gap energy decreases while the static refractive index changes, passing through a maximum value at 350 nm. The changes in non-linear refractive index n₂, third-order polarizability χ⁽³⁾, and F-function with light energy consist of the two-photon absorption and intensity-dependent refractive index conditions of optical non-linear characteristics. The maximum values of 7.67x10^-11 and 5.08x10^-12 esu attained at the film thickness of 350nm, of n₂, χ⁽³⁾,  respectively as a result of the compromise of different factors, such as the bound oxygen bonds and free ions, refractive index, localized state density, and number of crystallites, are better than the corresponding reported results for some oxide, chalcogenide, and organic materials.