A novel composition using 2,2,6,6-tetramethylpiperidinyloxyl (TEMPO) and dicurnyl peroxide (DCP) for scorch delay and control of the Final network topology of polydimethylvinylmethylsiloxane (vinyl-PDMS) at high temperatures has been proposed. The evolution of linear viscoelasticity during cross-linking reaction was carried out on parallel plate geometry rheometer. The rubber was cross-linked with different ratios of [TEMPO]/[DCP] in order to control scorch time, which is defined as the time during which the PDMS rubber can be worked at a given temperature before cross-linking begins (i.e., the time at which the complex shear modulus suddenly increases). We showed that. scorch delay increases according to the amount of TEMPO acting as in inhibitor. Nuclear magnetic resonance spectroscopy (H-1 NMR) has been used to investigate the effect of TEMPO. This study reveals that the delayed action is the result of a TEMPO-grafted polymer action formed by reaction between TEMPO and polymer radicals. Furthermore, polymeric radicals are rapidly trapped by a grafting reaction before they are able to form cross-links. The cross-linking density (nu) and the number of junctions (p) have been obtained from the phenomenological network model of Langley and Dossin and Graesslev. In addition, a differential scanning calorimeter (DSC) was used to characterize the cross-linking reaction. Specific heat data show two exothermic reactions. These reactions may be associated oil one hand to the decomposition of DCP and TEMPO grafting in vinyl-PDMS and oil the other hand to the C-C covalent bonds creation. The DSC results indicate that the variation of scorch time with the [TEMPO]/[DCP] ratio is in reasonable agreement with those obtained from rheological measurements. Finally,an original method based oil DSC experiments was derived to estimate the density of chemical junctions in PDMS networks. This method is based oil the balance between the enthalpy of created crosslinked bonds and the standard enthalpy for one covalent carbon-carbon bond. Interestingly, predicted numbers of chemical junctions are in close agreement with those calculated using viscoelastic data.