The behaviour of visual purple at low temperature

Abstract

Visual purple is soluble and stable in a mixture of glycerol and water (3:1). At room temp. the spectrum of such a soln. is identical with that of the aq. soln. At [long dash]73[degree] C the peak of the absorption curve is higher and narrower than at room temp., and it is shifted towards longer waves. The product of photodecomposition at [long dash] 73[degree] C has a spectrum independent of pH and is at low temps. thermostable and photostable, but at room temp. it decomposes thermally to indicator yellow. The primary product is identical with transient orange. The quantum yields of the photoreaction at low and at room temp. are of the same order.