An electronic simulator for transient processes

Molecular relaxation processes are often manifest through the transient changes in the optical properties of solutions of the molecules. Relaxation times are currently obtained by analysing the coordinates of photographic records of the transient behaviour and plotting suitable semi-logarithmic graphs. This procedure is laborious. A device is described herein which obviates this procedure. It enables experimental transient curves to be simulated almost immediately for the three important cases: (i) where a single exponential process is involved; (ii) where two such processes are summed together in the final response; (iii) where two such processes act in opposition in the final response. The last case is extremely difficult to analyse by the conventional geometric method mentioned above. Details are given of the design of the simulator and its mode of use. Typical results for each of the cases (i), (ii); (iii) are given with reference to measurements of the Kerr effect (electrically induced double refraction) of dilute macromolecular solutions.