Dipole-dipole relaxation of paraelectric impurities

Paraelectric impurities can relax via dipole-dipole interaction. This mechanism requires a statistical distribution of strong internal electric fields. The combination of relaxation via this process and via the coupling to the phonons can show a maximum in the relaxation time vs. temperature curve. The theory is applied to the paraelectric relaxation of OH-dipoles in KCl under two-dimensional compression.