Poly [methyl (3, 3, 3-trifluoropropyl) siloxane] with a 50% substitution of trifluoropropyl radical has been studied by inverse gas chromatography (IGC) between 90 and ISO C. Both packed and capillary columns have been used, thelatter prepared with and without cross-linking of the polymer. Flory-Huggins solute-polymer interaction parameters and partial molar enthalpies andfree energies of solution and mixing were calculated for 21 substances (ketones, alcohols, aromatic and saturated hydrocarbons, nitriles, esters, and dimethylaniline). Nitriles, tertiary amines, and ketones behave as good solvents. Aromatic hydrocarbons are moderate solvents if a hydrocarbon chain is not attached to the aromatic ring, while alcohols and alkanes are nonsolvents in the temperature range considered, althoughsolubility increases slightly with temperature. The thermodynamic functions vary linearly with the number of carbon atoms of the alkyl chain in homologous series. The solubility parameter of the polymer varies linearly with temperature from about 7.9 (cal cm'3) 1/2 at 90 Cto 7.4 (cal cm'3) 1/2 at 180 C. A value of 8.2 (cal cm" 3) 1/2 may be deduced for ó2 at 25 C. No meaningful difference was found betweenvalues deduced from Vg data obtained on packed or capillary columns, cross-linked or not.