THE CIS-TRANS ISOMERIZATION OF AZOBENZENE IN THE MOLTEN STATE - A USEFUL TEST REACTION FOR THE KINETIC EVALUATION OF DSC MEASUREMENTS

Contrary to the situation in the field of temperature, heal and heat f low rate calibration, so far no generally accepted and easily practica ble chemical reaction exists with regard to a kinetic evaluation. A po ssible reaction would be the well-known first-order cis-trans isomeriz ation of subcooled liquid azobenzene. Surprisingly, the evaluation of measurements performed with a power compensated calorimeter yields act ivation parameters, which are dependent on the hearing rate. The desme aring of the curves does not produce any improvements. However, consta nt activation parameters are obtained, if a small self-heating of the sample during the exothermic reaction is taken into account.