Modal characterization carried out reported in this paper was aimed determining the refractive index and thickness profile of Ag+/Na+ Ion Exchanged planar waveguides formed in Soda Lime Glass. Modal characterization was carried out using prism coupling technique and applied to all waveguides fabricated at temperature of 240 °C, 260 °C and 280 °C and processed for different duration. It was shown that the number of modes tends to increase with the increase of both temperature and duration of ion exchange process.