Imperfections of Kissinger Evaluation Method and the Explanation of Crystallization Kinetics of Glasses and Melts

The evaluation of nonisothermal thermoanalytical kinetics is simplified without the description of heat transfers, such as thermal inertia, which is not negligible, as indicated by Vyazovkin

“…19 It is clear that the long underestimated effect of thermal inertia can become a key factor in thermal analysis, which should primarily address heat transfer problems. 7,11,15,45 More and more attention is paid to this topic [26][27][28][29][30][31][32][33][34][41][42][43][44][45] and it is up to readers how far they will join it. It is obvious that the often questioned inertia of heat has not only a real but also a significant effect, the consequence of which is best seen in the reconstruction of inserted rectangular heat pulses, 36,[50][51][52][53] cf.…”

“…In addition to the previous one, Vyazovkin in his work 30 also dealt with the influence of thermal inertia in the evaluation method by Kissinger 40 and finds for larger samples an error in the calculated activation energy of up to 20%, which he considers negligible. The difference between the detected and the actual temperature of the DTA apex was analyzed in detail in the chapter 42 but in practical terms a more thorough revision by the ICTA kinetic committee is needed based on the analysis of larger sets of investigated samples. However, we must keep in mind that Kissinger's evaluation has become not only a very popular method, but also a relatively simplified approach that has gained many mathematical improvements not included here, 41,42 but none of these corrections directly addressed the impact of thermal inertia except 41–44 and in the future this will certainly require a separate study and publication following the chapter 42 …”

“…The assumed negligibility of the E‐error by up to 20% seems to be too high even for such mutually compensating measurements, including larger weights. The mathematics of peaks’ mismatch is analyzed in the chapter, 42 which of course again requires a deeper analysis with respect to these serial measurements 28,31,34 . This, of course, again requires a deeper analysis, which should become a demand of the future and a challenge for all members of the ICTAC Kinetic Commission, 17–19 and it is a pity that this has not happened so far.…”

“…The difference between the detected and the actual temperature of the DTA apex was analyzed in detail in the chapter 42 but in practical terms a more thorough revision by the ICTA kinetic committee is needed based on the analysis of larger sets of investigated samples. However, we must keep in mind that Kissinger's evaluation has become not only a very popular method, but also a relatively simplified approach that has gained many mathematical improvements not included here, 41,42 but none of these corrections directly addressed the impact of thermal inertia except [41][42][43][44] and in the future this will certainly require a separate study and publication following the chapter. 42 Recall that using runs under different heating, β, the Kissinger procedure provides an estimate of activation energy, E, as a slope of approximating line in the plot of ln(β/T mr 2 ) against -1/RT mr where T mr is substituted by temperature T mΔ at which an extreme of the peak on DTA curve (apex) is reached, that is, where the temperature difference ΔT = T S − T R between the sample under study (S) and the inert reference sample (R) attained its extreme value under assumed constant, β, for which the above condition is valid as dΔ mΔ T/dt = 0.…”

“…However, we must keep in mind that Kissinger's evaluation has become not only a very popular method, but also a relatively simplified approach that has gained many mathematical improvements not included here, 41,42 but none of these corrections directly addressed the impact of thermal inertia except [41][42][43][44] and in the future this will certainly require a separate study and publication following the chapter. 42 Recall that using runs under different heating, β, the Kissinger procedure provides an estimate of activation energy, E, as a slope of approximating line in the plot of ln(β/T mr 2 ) against -1/RT mr where T mr is substituted by temperature T mΔ at which an extreme of the peak on DTA curve (apex) is reached, that is, where the temperature difference ΔT = T S − T R between the sample under study (S) and the inert reference sample (R) attained its extreme value under assumed constant, β, for which the above condition is valid as dΔ mΔ T/dt = 0. However, Kissingerťs assumption 40 that the temperature T mΔ (in the point where temperature difference ΔT reaches the extreme value = Δ mΔ T) is identical with temperature T mr where the reaction rate r = dα/dt reaches its maximum is not correct at all!…”