TEMPERATURE-DEPENDENCE OF PRESSURE-SENSITIVE PAINTS

The photoluminescence properties of a typical pressure sensitive paint (PSP) formulation consisting of tris-(4,7-diphenylphenanthroline)ruth enium(II) dichloride (RudpCI) dispersed in a polydimethylsiloxane (PDM S) binder were examined as a function of temperature, Thus, the temper ature dependence of the luminescence intensity I-em and emission decay lifetime tau(em) of the PSP formulation and for the photoluminescent RudpCl dye dissolved in ethanol solvent were determined for temperatur es ranging from 5 to 50 degrees C, Analysis of the experimental data i ndicates that under deoxygenated conditions the temperature dependence of I-em and tau(em) for either the PSP formulation or ethanol solutio ns is dominated be the intrinsic temperature dependence of the nonradi ative decay rate of the photoluminescent dye molecule. By contrast, fo r the PSP formulation at 1-atm air pressure the temperature dependence of I-em and tau(em) is dominated by the temperature dependence of the diffusivity of oxygen in the PDMS binder. The implications of the exp erimental results on the design and application of PSP formulations ar e discussed.