Low-temperature behaviors such as glass transition, crystallization and crystalline melting for deswollen poly(dimethylsiloxane) (PDMS) networks were investigated by differential scanning calorimetry (DSC) as a function of polymer volume fraction at preparation (phi). The deswollen networks were made by removing the solvent from the PDMS gels prepared in solutions. For the gels prepared at low phi, much loss of the solvent in deswelling causes large decrease of the gel volume, which is expected to result in supercoiling, i.e. to make conformation of the network chains more compact relative to random-coil. The deswollen networks of high phi (greater than or equal to 0.44) showed neither the crystallization nor the melting-recrystallization behavior during heating process while the precursor linear PDMS did, which suggests that introduced crosslinks and trapped entanglements are against crystallization. Thermal behavior for modest low phi (approximate to 0.2) was similar to one of the precursor lineal PDMS due to reduction in trapped entanglements by crosslinking at the low polymer concentration. In spite of smaller number of trapped entanglements, the deswollen networks of the lower phi (less than or equal to 0.14) showed neither the crystallization nor melting-recrystallization. The phi dependence of degree of crystallinity had a maximum at phi approximate to 0.2, and the values for phi less than or equal to 0.14 were definitely smaller than the maximum value. The anomalies for the phi dependence of thermal behavior and the degree of crystallinity in phi less than or equal to 0.14, strongly suggests formation of a considerably shrunken conformation (supercoiling) which inhibits the crystallization and the melting-recrystallization during heating process, and depresses degree of crystallinity. (C) 2000 Elsevier Science Ltd. All rights reserved.