Ultra-violet pulse response of sodium salicylate

The ultra-violet pulse response and the associated time constant have been determined for sprayed sodium salicylate coatings of thickness 0·1-20 mg cm -2 , for three solvents (water, methanol and ethanol) and for primary radiations in the range 2200-3400 Å. The ultra-violet light source was a pulsed nitrogen arc of 30 A current, 10 nsec duration and 400 pulses/sec repetition frequency. The primary and fluorescence light pulses were detected by a photomultiplier-sampling oscilloscope system. The ultra-violet pulse response of the coatings was found to be independent of coating thickness, solvent and primary wavelength, and could be described by a single exponential decay time of 7 ± 1 nsec. The discrepancies between this value and those previously published are discussed.