Second-harmonic generation in Langmuir-Blodgett films of a number of azobenzene derivatives

Second-harmonic generation was used in an investigation of the quadratic optical susceptibilities and of the structure of Langmuir-Blodgett films of a number of azobenzene derivatives, The angular distribution of second-harmonic radiation could differ significantly for films containing domains with the average size r considerably less than the second-harmonic wavelength lambda and films consisting of relatively large domains (r much greater than lambda). The orientation of the molecules relative to the substrate was determined in both cases.