Trace amount of solvents such as n-octane, n-nonane, n-decane, isopropyl acetate, tert-butyl acetate and isoamyl acetate were passed through the column of a gas chromatograph, which stationary phase is poly (phenyl sulfone) trademarked as Radel(R)R. The retention diagrams were obtained by plotting the logarithm of the specific retention volumes of the solvents against reciprocal of the absolute column temperature between 50 and 280 degreesC. The slope changes on the diagram were assigned as secondary transitions. Three secondary transition temperatures were established at 140, 110 and 80 degreesC below glass transition temperature, 210 Cdegrees. Weight fraction activity coefficients of the solvents at infinite dilution, Omega(1)(infinity) and hard-core polymer solvent interaction parameters chi(t)(infinity) were given for the studied solvents at 250 degreesC. The values of the parameters Omega(1)(infinity) and chi(t)(infinity) suggest that n-alkanes are very poor whereas esters studied are moderately poor solvents for poly (phenyl sulfone) at 250 degrees C.