Temperature dependence of the lifetime of phosphorescence of some polynuclear hydrocarbons in viscous solution

Abstract

In viscous solutions, the rate of decay of the triplet state, as followed by phosphorescence measurements, is a strong function of temperature at normal temperatures and becomes nearly independent of temperature at low temperatures. The experimental data were described best by an equation of the form :where a is the limiting value of the rate constant at low temperatures, and b and E l , and c and E2 are the low-and high-temperature pre-exponential factors and activation energies, respectively.

Techniques for Measuring Fluorescence and Phosphorescence of Biological Materials*

“…That these quenching processes can be eliminated by using solvents with high viscosities was known from the early work of Wiedemann and Schmidt [33]: these workers observed both phosphorescence and delayed fluorescence from organic materials in gelatin, sucrose or boric acid glasses at room temperatures. The alternative of removing the quencher by purging with helium or degassing is not successfu1 [30][31][32]; the methods that have to be adopted, such as refluxing or repetitive freeze-thaw cycles against a high vacuum, would denature proteins or nucleic acids. The simplest method to eliminate oxygen quenching of the triplet states is to work with glassing solvents at 77°K.…”