Laser irradiation of single crystals of doped Ag(CN)(2)(-)/KCl and pure KAg(CN)(2) at 77 K results in dramatic changes in their emission spectra. Higher-energy bands that were either absent or weak start appearing concomitant with a quenching of the original major lower-energy bands as samples are exposed to 266 nm laser light. These changes are progressive with increased irradiation time and they are also reversible. Thus, when a given crystal is heated from 77 K to ambient temperature and then re-cooled to 77 K hysteresis occurs as the original luminescence spectra before irradiation are obtained. Two doped Ag(CN)(2)(-)/KCl single crystals with Ag content of 1.21 and 2.23% (wt) as well as pure single crystals of KAg(CN)(2) show this "write/read/erase" effect to various extents. By analyzing the luminescence profile versus exposure time to 266 nm laser irradiation at cryogenic temperatures, it was possible to calculate the rate constants for the forward (k(1)) and reverse (k(2)) reactions of the writing process. The fastest changes are for the 1.21% doped crystals (k(1) = 0.04493 min(-1)), followed by the 2.23% doped crystals (k(1) = 0.01245 min(-1)) while the slowest changes were for pure KAg(CN)(2) (k(1) = 0.00178 min(-1)). The results were explained in terms of a change in the distribution of *[Ag(CN)(2)(-)](n) excitons with different geometries following laser irradiation.