THE DIELECTRIC-RELAXATION BEHAVIOR OF M-FLUOROANILINE ABOVE THE GLASS-TRANSITION

The dielectric properties of m-fluoroaniline have been investigated ov er seven decades of frequency (1 kHz-20 GHz) in the temperature range 188-303 K, above the calorimetric glass transition temperature. The Ar rhenius plot of the inverse alpha peak frequencies reveals a non-linea r character and a non-Debye relaxation function indicates a non-expone ntial temporal decay of the molecular polarization of the liquid near T-g. The dynamic behaviour turns out to be typical of highly fragile l iquids and appears closely similar to that obtained from previous ultr asonic studies on the same system. A crossover between two distinct dy namical regimes takes place in the range of intermediate viscosity at a temperature T-c which falls about 40 K above the glass transition te mperature T-g.