Bicyclo[2.2.1]hept-2-ene-5-yl (norborn-2-ene-5-yl) derivatives of silic acid were synthesized by the Diels-Alder reaction of the corresponding (meth)acryloxypropyl silanes with cyclopentadiene monomer. The norbornenyl silanes were characterized by elemental analyses, IR, H-1 NMR, C-13 NMR and Si-29 NMR spectroscopy. The hydrolysis and condensation of norbornene-funktionalized silic acid esters yield polysiloxanes which can be crosslinked by the photoinitiated reaction with multifunctional thiols. The shrinking behaviour of the bulk materials which are obtained by this combination of the sol-gel process with the thiol-ene polymerization were investigated.