EN
The present work is devoted to investigation of optical absorption changes in Fe and Cu doped LiNbO₃ (LNO) single crystals induced during annealing in vacuum and air as well as under influence of the ²⁰⁹Bi ions irradiation with energy 11.4 MeV/u (MeV per nucleon) and a fluence 5×10¹¹ cm¯² at room temperature. The analysis of changes of absorption of the crystal during air annealing have been studied in the Arrhenius coordinates and activation energies have been determined.