SiO2(porous glass)-PbF2 composites were fabricated by reaction between Pb(NO3)(2) and NH4F solutions within micropores of porous glass pellets at room temperature. They were compared with Al2O3(porous alumina)-PbF2 composites in terms of phase stability, grain orientation, crystallite size and lattice distortion. The deposit in the SiO,-PbF, composites consisted of exclusively beta-PbF2, while that in the Al2O3-PbF2 composites consisted of alpha-PbF2 and beta-PbF2. The grains in the SiO2-PbF2 composites showed virtually no preferred orientation, while those in the Al2O3-PbF2 composites showed significant grain orientation. The crystallite size of the PbF2 grains in the SiO2-PbF2 composite was much smaller than the Al2O3-PbF2 composite.