The Formation of Sodium Nanoparticles in Alkali-Silicate Glass Under the Action of the Electron Beam and Thermal Treatments

It is shown experimentally that the processing of the sodium-containing silicate glasses with the electron beam with electron energy 35 keV and dozes 20–65 mC/cm2 and the subsequent thermal treatment above the glass transition temperature result in the formation of the metallic sodium nanoparticles under the glass surface that manifest themselves in the plasmon resonance absorption band in the 405–410 nm spectral region. The main mechanisms of this effect are the field migration of the positive sodium ions into the negatively charged region under the glass surface, produced by the thermalized electrons, reduction of sodium ions by the thermalized electrons, and the nanoparticles growth as a result of thermal diffusion of the sodium atoms during the thermal treatment. The computer simulations in the dipole quasi-static approximation have shown that the most realistic model of the nanoparticle structure is the solid or liquid sodium core with two shells—the inner shell consisting of sodium oxide and the external one being vacuum or gas.