Glass-like dielectrics are studied by methods of plasmon dispersion and asymmetry of the number of localized electrons in the zone of formation of the total external reflection of x-rays and the excitation of plasma vibrations. Defined by the internal mechanical stress and the associated polarization of the investigated dielectrics. The absence of internal mechanical stress in a single crystal of lithium fluoride was found out, and the observed polarization is caused by a large macroscopic dipole moment in this single crystal