A high pressure study of the effect of viscosity on the light induced isomerization of DMABN in three linear alcohols, iso-butanol and glycerol

The light induced isomerization of 4-N,N-dimethylaminobenzonitrile (DMABN) has been measured versus pressure to 10 kbar in ethanol, n-butanol, n-pentanol, iso-butanol and glycerol. or the three straight chain alcohols a linear plot of log(ITICT/ILE) versus α log η (η=viscosity) was obtained with α = −0.5 ± 0.02. Iso-butanol gave a non-linear plot of the above variables and at any viscosity the value of ITICT/ILE was greater than for n-butanol, although those two alcohols have nearly identical values for their electronic and volumetric properties. The results for glycerol extend the viscosity range significantly and exhibit distinctly non-linear behavior for the above type of plot.