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 ($r\gg\lambda$). The orientation of the molecules relative to the substrate was determined in both cases.