The relaxation behavior of six fluorinated aromatic poly( ethers) was investigated using dynamic mechanical analysis. The glass transition temperature was found to increase as the size and rigidity of linking groups increased and varied between 168 degrees C for a dimethyl linking group and 300 degrees C for a bicyclic benzoate ether-linking group. For the alpha-relaxation the steepness of time/temperature plots and broadness of the loss curves could be qualitatively correlated with chemical structure in a manner predicted by the coupling model of relaxation. Well-separated sub-T-g transitions were also observed, as a shoulder on the low temperature side of the alpha-peak, and as a broad, low loss transition around -100 degrees C. The higher temperature process was similar to the structural relaxation often found in quenched glassy polymers, while the position, intensity, and breadth of the subambient process was sensitive to chemical structure.