Author's earlier data on thermal decomposition of solids (e.g. Ca oxalate, Ca carbonate, Cu sulfate, etc.) and complex materials (hard coal, pitch, paraffin oil-polyolefin-catalyst, etc.) were approached in terms of the relative rate of reaction vs. temperature relationship. The original equation Inalpha = a(0) - a(1)/T - a(2)InT was modified to Inalpha = -a(3) + a(4)/T + a(5)InT and consequently, r = -a(4) + a(5)T (a = degree of transformation of solid phase; r = -dInalpha/d(1/T)). This gave more information on phys. transformations (e.g. sublimation of coronene). A new interpretation of the r vs. T relationship was provided for the simplest case of linear wt. (TG) change with temperature (T). In technological studies, complicated thermodynamic considerations were thus omitted in favor of linear relationships valid within well-defined temperature ranges.