BRILLOUIN-SCATTERING OF AEROGELS DENSIFIED UNDER UNIAXIAL PRESSURE

A Brillouin scattering investigation was conducted on aerogels densifi ed under uniaxial pressure. Sound velocity and elastic modulus as a fu nction of the applied pressure and resulting density were examined. No evidence of elastic anisotropy was observed. The frequency of the pho non-fracton crossover and fractal persistence length were determined a s a function of density and a comparison was made with series of mutua lly self-similar samples. (C) 1998 Elsevier Science B.V. All rights re served.