Utilization of constant heating rate DSC cycles for enthalpy relaxation studies and their influenceability by erroneous experimental operations

The utilization of the constant heating rate cyclic temperature history was examined with respect to enthalpy relaxation studies. In this regard, three main methodologies for the determination of structural relaxation parameters were described in detail - curve-fitting, simulation-comparative methods and determination of activation energy according to Moynihan. Advantages and disadvantages of the constant heating rate cycles were introduced for each of the methodologies. In addition, Moynihan's method was extensively tested for all types of relaxation behavior and its accuracy has been determined. Main emphasis was then put on the utilization of the unique shape of the constant heating rate cycles for the identification of certain data-distortive effects caused by erroneous experimental operations. A discussion of all possible data-distortive effects was conducted; the manifestation of these distortions with respect to the relevant evaluation methodologies was demonstrated on theoretically simulated data. For each data-distortive effect, a universal and easy-to-apply practice was suggested to recognize and account for the given data-distortion.