Abstract
The temperature dependences
of the phosphorescence decay from the triplet state of naphthalene embedded in
3- methylpentane/methylcyclohexane mixtures of different compositions in the
presence and absence of oxygen have been determined and are presented as
Arrhenius plots. In the presence of oxygen, the slopes of these plots above the
glass transition temperature depend on the composition of the mixture. It is
shown that the effect of solvent composition in this temperature region can be
explained by interactions between the solvent molecules which affect the
activation energy of diffusion of the oxygen which is quenching the triplet
state of naphthalene. ��� In the absence of oxygen, the effect of
solvent mixture composition is small, and it is suggested that the deactivation
of the triplet state is affected by steric constraints imposed by the
surrounding molecules.