This project concerns the characterization of nanocomposites of ferrite oxide (NiFe2O4) and carbon black in poly-metal methacrylate (PMMA) for optical power limiting (OPL) applications. This is due to their non-linear optical properties and behavior at nanosize. Polymers show an improvement in properties when they are alloyed with nano-fillers. The polymer-based nanocomposites which are used for OPL applications need to be characterized for particle distribution in relation with their optical properties, milling time and particle concentration. To determine the particle distribution, the fracture surface was analyzed by SEM. Some samples were also dissolved in order to only investigate the particles in the SEM. Sample preparation required for SEM investigation is presented and the difficulties that occur along the process are described.