The reactions of electrons in alkaline glasses containing 5-20 M NaOH were studied by isothermal luminescence (ITL) after γ-irradiation at 77 K and by radiothermoluminescence (RTL). Both ITL and total RTL emission are influenced by NaOH concentration in a similar way revealing a minimum at 8-10 M NaOH. The RTL emission exhibits two broad peaks. The low temperature peak (98±3 K and 107±3 K for 5 M and 20 M NaOH, respectively) is only slightly dependent on matrix composition. The position of the high temperature peak shifts with the glass transition point of the matrix from 179±3 K for 6 M NaOH to 236±3 K for 20 M NaOH. The contributions of these peaks to the total RTL emission can be correlated with concentration of trapped electrons (e -x), H atoms, (Na +…e -) t pairs and O - radicals. It is suggested that ITL and the low temperature RTL peak are possibly due to the radiative tunnelling of e -t to H atoms and radiative capture of electrons by alkali metal cations. The former mechanism is dominant formatrices containing less than 8 M NaOH, the latter for the higher concentrations of solute. The high temperature RTL peak is mainly associated with the radiative recombination of e -t with O - radicals.