In this dissertation we describe the preparation of gold nanoparticles (NPs) by heating gold thin films of thicknesses between (6-20) nm, previously deposited on soda-lime substrates by Magnetron Sputtering. Also described are the morphological and optical (linear and nonlinear) characterization of the NPs. The tempertature dependence of the formation process of the NPs was investigated. The samples were structurally characterized by Atomic Force Microscopy (AFM) and Scanning Electron Microscopy, High Resolution (FESEM). We used an image analysis (IA) before extraction of morphological features involving the steps of preprocessing, segmentation, post-processing and measurement. For the processing and extraction of attributes, we used the software KS400. The particles have nanometers dimensions with approximately spherical shape and diameters around 13 nm for NPs formed by heating 6 nm thick thin films at 600 ° C for 4 minutes. The linear and nonlinear optical characterization of the NPs were performed through the techniques of UV-Vis spectroscopy and (TM-EZ at 532 nm, respectively. The non-linear optical characterization yielded the nonlinear refractive index (n2) and nonlinear absorption (a2) of the gold NPs formed. The results revealed high linear refractive indices, as well as a sign inversion of the nonlinear absorption when the NPs were formed.