Dielectric behavior and percolation phenomena in porous silica gels

The purpose of the present Letter is the use of dielectric relaxation for investigating percolation phenomena in sol–gel glasses with different catalysts. The broadband dielectric spectroscopy method was employed to investigate glasses of fine porosity produced via the sol–gel route with different catalysts. The study was carried out in the frequency range of 20 Hz to 1 MHz and temperature interval −100°C to +150°C. The dielectric response data were analyzed both in frequency and time domains and then interpreted in terms of the various non-Debye relaxation processes. The mechanisms of the processes are discussed. One of them is associated with percolation of electric excitation along the developed fractal structure of connected pores.