Chapter 2 – Photophysical, Photochemical and Photokinetic Properties of Photochromic Systems

This chapter describes the principles of photokinetics and discusses the possibilities and problems of the calculations of reaction constants. It discusses how the usual rate laws are expanded to be usable for the evaluation of photoreactions in polymeric systems. The chapter also outlines some new methods that combine spectroscopic and chromatographic data to increase information obtainable during reactions. All these considerations are a prerequisite for obtaining information beyond overall yields and possible photoproducts. Any determination of quantitative values demands laborious studies. The chapter demonstrates that such examinations allow thermal rate constants and partial photochemical quantum yields to be calculated with enough precision to compare them for different conditions of the reaction. This result offers the chance to control and optimize the reaction pathways of photochromic systems.