Dielectric dispersion measurements of salt-water-saturated porous glass

Abstract

Porous-glass specimens with different porosities were made from glass spheres of diameter 0.2–0.3 mm. The cylinder-shaped specimens were filled with salt water with resistivity varying between 0.1 and 500 Ωm, and the two-terminal admittance of these specimens was measured in the frequency range 5 Hz to 13 MHz. The dielectric constant and conductivity of a specimen as functions of frequency, with water resistivity as parameter, were both reduced to one single curve when plotted as a function of reduced frequency ω/${\omega }_0$, where ${\omega }_0$ is the relaxation frequency of the fluid. The highest relaxation frequency of the specimens was measured to be ${\omega }_0$. The Lysne-Bergman relaxation-frequency density spectrum of the specimens can be given by g($s_n$) =${\mathrm{Cs}}_n^{\mathrm{-}b}$ ${\exp \mathrm{\{}\mathrm{-}[\log }_{10}$/B ($s_n$/D${\left)\right]}^4$}+$F_1$δ($s_n$-1), where $s_n$ is the relaxation frequency, b=0.84±0.04, while C, D, and $F_1$ are porosity dependent.