[en] We evaluated mechanical, thermal, thermodynamic, and chemical properties of Dow Corning DC-S-2000, a silicone rubber filled with silica, that was selected as an O-ring material for SHIVA laser amplifiers. We compared the properties of a batch cured in-house with the manufacturer's specifications, and we developed specific quality-control tests to evaluate future production batches of this elastomer. We also examined mechanical and thermal transitions not described in the manufacturer's bulletin. Because the silicone O-rings must function under prolonged compression, we recommend an examination of the compression properties of DC-S-2000