Abstract
Intrinsic viscosities were measured for sharply fractionated polymer in a good solvent and in a poor solvent at several temperatures. They increased with specific volume of the solute, [η] = ΦL3/M. Φ was considered as an empirical constant depending on solute and solvent. Values were determined for polystyrene/toluene and polystyrene/cyclohexane, using light‐scattering measurements for derivation of molecular weights and dimensions. The equation was assumed valid for extrapolation to lower molecular weights and used to estimate molecular dimensions from viscosity/molecular weight data in a range not directly measurable. The results were compared with theoretical calculations of the random coil problem.