Production and conversion of color centers in OH−-doped KCl polycrystals colored electrolytically

OH−-doped KCl polycrystals are colored electrolytically by using a pointed cathode and a flat anode at various temperatures and voltages. Characteristic O−, OH−, U, UA and Cu+ absorption peaks are observed in resolved absorption spectra of uncolored polycrystals. Characteristic V2, V3, Cu+, O2−-Va+, I2-, I2, H2O− and F spectral bands are observed at room temperature in Kubelka-Munk functions of colored polycrystals. Current-time curve for electrolytic coloration of an OH−-doped KCl polycrystal and its relationship with electrolytic coloration process are given. Production and conversion of color centers are explained.