Dielectric and elastic responses of nanostructured sodium nitrite in a porous glass

The dielectric and elastic properties of the SiO₂-NaNO₂ nanocomposite obtained by incorporation of sodium nitrite into a porous glass matrix with an average pore diameter of ≈7 nm have been investigated in the temperature range 300–550 K. A significant softening of the shear modulus has been revealed in the temperature range 380–520 K, which corresponds to the premelting region of the embedded material. Analysis of the dielectric response spectra at frequencies from 1 Hz to 2.5 MHz has revealed four relaxation processes, two of which are thermally activated. The nature of the relaxation processes is discussed.