Experimental studies of the ortho-toluidine glass transition

The thermodynamic and dynamics proprieties of ortho-toluidine, in the vicinity of a glass transition, have been studied by calorimetric and by two light scattering techniques, depolarized light scattering and time-resolved optical Kerr effect. Differential scanning microcalorimetry clearly detects a glass transition in o-toluidine and it measures some thermodynamics critical parameters, in particular, the transition temperature. The light scattering data have been analyzed according to the mode-coupling theory. This theory gives a good interpretation of our data and it allows to extract safely the critical parameters of the o-toluidine dynamics. We found a fair agreement between the analysis outputs performed in the frequency domain and in the time domain. Finally, we compared the glass transition features of o-toluidine with that of its isomer meta-toluidine, looking for some general idea about the molecular aspects of the glass transition.