Transition, first-order autocatalytic

In the case of tetra-methyl-l,2-dioxetane [(6.75)], the luminescence originates from triplet acetone which is formed directly from the starting material. In the presence of oxygen, the decomposition reaction is first order in dioxetane in the absence of oxygen in hydrocarbon solvents, the destruction of dioxetane is second order in dioxetane and appears to be autocatalytic in triplet acetone. Impurities in hydroxylic solvents (presumably transition metal ions) can catalytically quench the luminescence however, in the presence of lanthanide ions, the chemiluminescence is quite efficient, with emission occurring from lanthanide excited states. 

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