Аннотация:The photochromic transformation of color centers in γ-irradiated Ca1−xYxF2+x yttrofluorite crystals with disordered crystal lattice formed in the binary system of CaF2–YF3 solid solutions at different contents of yttrium fluoride has been studied. The photochromic transformation of РС+ centers into a РС center was shown to occur under UV irradiation. It was found that the participation of UV-induced photoelectrons of γ-induced F-centers should be taken into account in the consideration of the mechanism of РС+ → РС transformation. An effect of the structure disordering on the increase in the intensity of absorption spectral bands of РС color centers is revealed.