Samples of virgin and a crosslinked fluorinated rubber, containing different amounts of carbon black and solvated with methylethyl ketone, have been investigated by differential scanning calorimetry. Although the polymer-solvent interaction increases with decreasing temperature, a process of solvent separation was observed for all of the systems. This process can be attributed to a T-g regulation effect in which solvent crystallization occurs only when the crystallization temperature is higher than the T-g of the system. The interaction between rubber and filler, approximately temperature independent, was found to not influence the glass transition of the rubber-methylethyl ketone systems, even when the carbon black content is on the order of 35 wt %.