In a soda-lime glass provided by Companhia Vidraria Santa Marina, subsidiary of French Saint-Gobain, we induced a gradient of refraction of index (GRIN) by exchange of Na+ in glass by Li+ at 550ºC for 12, 24, 36 and 48 hours and varying bath temperature at 525ºC, 550ºC, 575ºC and 600ºC for fixed time of 48 hours. deltan = 0.0107 ± 0.0005 and GRIN depth of about 2.4mm were obtained for the ion exchange at 550ºC for 48 hours. The GRIN profile was fitted with er fc(x) function and then obtained the diffusion coefficient D = (1.6 ± 0.3) · 10-6 mm²/s.
