The existence of the candoluminescence phenomenon and the underlying mechanism have been the subject of extensive research and debate since the first reports of it in the 1800s.
[1] Extremely narrow-wavelength emission by the combustion products is often an important feature in this process, because it reduces the rate at which the free radicals lose heat to radiation at invisible or non-fluorescence-exciting wavelengths.
In other cases, the excited combustion products are thought to directly transfer their energy to luminescent species in the solid material.
Early in the 20th century, there was vigorous debate over whether candoluminescence is required to explain the behavior of Welsbach gas mantles or limelight.
[4] Another argument was that the oxides in the mantle might be actively absorbing the combustion products and thus being selectively raised to combustion-product temperatures.