The following graph shows typical CL behaviour during heating measurement. As the sample is heated, the peroxide decomposes, and CL from the excited carbonyl increases, resulting in a peak (the first peak). This corresponds to the amount of peroxide at that point.
The oxidation reaction is then accelerated by heating in air or oxygen, and eventually the CL reaches a steady state. The intensity at this time is termed the steady-state luminescence intensity (Is). In the sample to which stabiliser has been added, the stabiliser is consumed, the steady state of the oxidation reaction is disrupted, and the amount of radicals in the sample increases, resulting in the appearance of significantly higher luminescence (the second peak). This point is called the oxidation induction time (OIT). The OIT can be used to evaluate the oxidative stability of the sample. Also, since Is is the steady state of radical extinction and formation within the sample, it represents the rate of radical generation, and this value can also be used to evaluate the oxidative stability of the sample.