[en] Studies on electron trapping in 8 and 18 mol.dm^-3 NaOH glassy ices were performed by means of 4 K γ-irradiation technique. The optical absorption spectra of e sub(t)sup(-) were found to be considerably red-shifted and broader compared with the spectra with the spectra in the ices irradiated and examined at 77 K. This trend was more pronounced for the concentrated sample. The red part of the broad spectra was removed either by photobleaching with light of lambda > 800 nm at 4 K or by thermally annealing at 77 K. These results, combined with electron spin resonance data, lead to the conclusion that the shallow electron traps responsible for the red part of the spectra are formed with the participation of Na⁺ cations in the alkaline ices. (auth.)