Effects of annealing electric field assisted K+-Na+ ion exchanged soda-lime glass guides

Soda-lime glass samples have been subjected to either a thermal or an electric field assisted K+-Na+ ion exchange. The effective refractive indices of the modes supported by the guides have been measured using a prism coupler before and after annealing and refractive index profiles have been reconstructed from the data. The effective refractive indices of the modes for guides produced by electric field assisted exchange exhibit an unusual evolution with annealing time. The area under the refractive index profiles produced from the measurements shows a significant reduction with annealing time. These features are not present in samples prepared by thermal ion exchange. The results are attributed to a relaxation mechanism operative only within regions of the glass that have been subjected to field assisted K+ ion injection.