The behavior of alkali‐halide electrets of and double doped , OH is investigated by the glow peak discharge method of Fieschi, Bucci et al. (1) (ionic thermal conductivity method or ITC). In this case a complete analysis of the trapped polarization is possible quantitatively. The electret polarization is due to impurity vacancy dipoles. It is shown that the electret behavior in this case can be used as a very powerful tool to investigate the motion of defects in the solid matrix. As an application, the dipole diffusion to form higher aggregates is studied by a thermal annealing technique. By studying the variation of the electret released charge for various temperatures it is shown that trimers (3 dipole aggregates) are formed. The reaction is found to be of third order, and the activation energy for defect motion is (0.71 ev). The dipole relaxation frequency at 0°K is 10−13 sec−1. All data agree very well with that obtained by other techniques and confirms the results of Dryden and Cook (2). In the case of double‐doped systems, it is shown that the ITC method allows a quantitative determination of the solid‐state reaction between OH and Ca. A correlation between F center formation by x‐irradiation and electret behavior is also found, showing that the reaction is probably the precipitation of in the matrix leading to dipole destruction and quenching of the color center production. This is perhaps the only case in which the electret behavior is completely understood in a quantitative way, and, used as a tool, to obtain important solid‐state parameters such as relaxation times, number of defects in the matrix, activation energies, and to investigate defect production and reactions in the solid state.