Laser Raman spectroscopy was used to study the dissolution of volatile hydrocarbon molecules in thin films of poly-alpha-olefin oil. Above the boiling point of the hydrocarbon, or when no liquid hydrocarbon was present, the dissolution was driven by Henry’s law solubilities in line with previous models. However, below the boiling point and when significant Liquid hydrocarbon was present, dissolution was entropically driven. Under these conditions, where equilibrium solubilities were not achievable, the Raman spectra were used to determine hydrocarbons, pressure and temperature influenced the dissolution rate primarily by affecting the vapor pressure and concentration of the volatile hydrocarbon. The rate-limiting step for the dissolution involved mass transport at the vapor/film interface.