Low-temperature luminescence of lead silicate glass

The temperature quenching of intrinsic luminescence of a lead silicate glass of the 20PbO center dot 80SiO(2) composition has been investigated in the temperature range 7-200 K. It has been found that the temperature behavior of the intensity of intrinsic luminescence does not obey the well-known Mott's law for intracenter quenching of luminescence but is adequately described by the empirical Street's formula. It has been demonstrated that, with allowance made for the disorder of the atomic structure, the experimental temperature dependence of the luminescence intensity of the glass can be represented as a superposition of Mott's dependences for an ensemble of local luminescence centers. The obtained distribution of luminescence centers over the activation energies of quenching has an asymmetric form with prevailing low-energy states. It has been assumed that this feature has a general character and, at low temperatures, determines the specificity of the processes of nonradiative relaxation of the electronic subsystem for many oxide glasses.