The crosslinking of poly(dimethylsiloxane) elastomers and coatings by the thermal curing of poly(dimethylsiloxane-co-methylvinylsiloxane) and 1,12-diazido-dodecane was studied. This crosslinking pathway relies on the cycloaddition of azides and alkenes as well as the thermal generation of nitrene transient radicals, which react with alkenes, yielding respectively 1,2,3-triazoline and aziridine crosslinking knots. The influence of temperature and the ratio of azide and vinyl functionalities has been investigated by rheological, swelling, and insoluble fraction measurements for materials crosslinked in bulk and by comparison of the thickness before and after extraction of the soluble materials by soxhlet extraction for the crosslinked coatings. The preparation of highly crosslinked PDMS-based elastomers and coatings has been demonstrated, even if the fraction of elastically effective crosslinks in bulk remained below 160 mol/m(3). Advantageously, this system does not require additional initiator or catalyst, is not sensitive to moisture or oxygen, and can be extended to a wide range of unsaturated polymers as well as different organic or inorganic solid substrates. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 50: 98-107, 2012