Influence of temperature on absorption spectra and second-armonic generation in azobenzen Langmuir-Blodgett films

The influence of temperature on the spectra and nonlinear optics properties of the 4(nitro) 4′aminoazobenzene compound Langmuir-Blodgett(LB)films were investigated using UV visible absorption spectra and second harmonic generation (SHG) technique. The SHG intensity of the monolayer LB films declined monotonically with the increase of temperature from room temperature to 80 ℃ and became faint when the temperature exceeded 80 ℃. The SHG intensity of the multilayer LB films decreased rapidly at first, then slowly, then kept steady, and then decreased when the temperature increased. The absorption spectra showed that the orderly arrangement of the molecule in the monolayer LB films was not easy to recovery after heating, and it could not recover when the temperature was above 80 ℃. But it