we demonstrate, for the first time to our knowledge, two different balances around fluorine-related non-paramagnetic color (fd) centers in fluoride containing phosphate based optical filter glasses at low (190 degrees c) and higher (390 degrees c) heat-treatment temperature, respectively. the thermal bleaching experiment results indicate the heat-treatment bleached gamma radiation induced phosphate-related oxygen hole center (pohc) and oxygen-related hole center (ohc) to some extent due to the release and capture of the electrons in the conduction band. through the gamma radiation and subsequent heat-treatment experiment, as well as the detailed analysis of photoluminescence and excitation spectra, a general model corresponding to the two different balances about the fd defects and the evolutionary mechanism of these existing defects in the fluoride-containing phosphate based glasses was proposed. (c) 2016 the electrochemical society. all rights reserved.