Al2O3 and Y(3)AL(5)O(12) singles crystals were irradiated by reactor neutrons at about 40 degrees C. After irradiation the generated point defects were investigated by optical absorption, thermoluminescence (TL) and differential scanning calorimetry (DSC) techniques. From the experimental data, it is found that 300 nm absorption band observed in Al2O3 and Y3Al5O12 crystals is attributed to Al-i(+) ion and O- - hole center localized near the cation vacancy respectively. It acts as hole traps with activation energies of 1.4 and 1.3 eV, respectively. Different annealing steps are observed and discussed in both Y3Al5O12 and Al2O3 crystals. (C) 2014 Elsevier B.V. All rights reserved.