Investigation of cleavage processes in photoinitiators: from experiments to molecular modeling

The present paper shows an original approach combining laser induced photoacoustic calorimetry (PAC) and molecular modeling for the investigation of the cleavage process in radical photoinitiating systems. The bond dissociation enthalpies (BDE) and the enthalpies for the photodissociation reaction ΔHrdiss of the photoinitiators are calculated and the quantum yields of dissociation φdiss from the excited state are determined. It appears that these quantum yields are not unity and do not correlate either with BDEs or ΔHrdiss.