We report on the preparation and characterization of two glass/conducting polymer nanocomposites obtained by the in situ oxidative polymerization of pyrrole and aniline inside the pores of Porous Vycor Glass (PVG), Oxidative polymerization of pyrrole was done via Cu2+ cation impregnated in the PVG pores. The polymerization of aniline was undertaken by impregnating PVG with the monomer, followed by an acid solution of (NH4)(2)S2O8. These nanocomposites were characterized by diffuse reflectance FT infrared spectroscopy, UV-Vis-NIR absorption spectroscopy, thermogravimetric analysis, Raman spectroscopy, solid state C-13 and Si-29 CP-MAS-NMR, scanning electron microscopy, transmission electron microscopy, cyclic voltammetry and conductivity measurements. The results showed that both polymers are formed inside the PVG pores in their oxidized conductive state, with the Si-O- groups bf the glass surface acting as counter-anions. The dimensions of the pores of the glass preclude cross-linking of the polymers, allowing only formations of linear chains. The results suggest the formation of polymeric wires in the bulk of the glass substrate. (C) 1999 Elsevier Science S.A. All rights reserved.993227235