POLYCARBOSILOXANE NETWORKS Polycarbosiloxane networks were obtained by the crosslinking reaction of bis(triethoxysilylethylene) cyclocarbosiloxanes. For this purpose 2,5-dimethyl-2,5-dihydro-3,4-diphenyl-1-oxa-2,5-disilacyclopentane and 2,7-dimethyl-2,7-dihydro-3,3,6,6-tetraphenyl-1-oxa-2,7-disilacycloheptane were modified with triethoxy-vinylsilyl groups via catalytic hydrosilylation. These monomers were characterized through spectral analysis by 1H-NMR, 13C-NMR and FT-IR. The crosslinking process of the cyclocarbosiloxane precursors was studied in various reaction conditions of temperatures and catalyst concentration. Using swelling measurements of the polymers in gelation state, the specific development of the polycyclocarbosiloxane network systems toward the final hyper-crosslinked state was investigated. Through this approach details concerning the influence of the precursor chemical structure over the characteristic evolution of the crosslinking process were revealed.