The aim of this work is to use the computational simulation to define the operational conditions to achieve the desired process. The diagnostic tests were used to guide the experiment where PVA composites doped with Titanium dioxide nanoparticles were irradiated with nitrogen laser in order to modify its properties. The temperature of the samples with different laser fluencies were simulated using finite element method, in COMSOL program, to predict the fluencies that is suitable to use for modification before reaching the decomposition temperature of the nanocomposite sample to make sure not to cause any damage. The optical and thermal properties were experimentally studied, and the results were used to define the absorption coefficient and the thermal conductivity of the studied nanocomposites