Third-order nonlinear optical response of push–pull azobenzene polymers

[Display omitted] ► Third-order susceptibility χ(3) of some azo-containing side-chain polymers. ► Transient and electronic nonlinear optical response of azobenzene molecules. ► The films exhibited very large NLO response of about 10−7 and 10−5esu under ps and ns laser excitation. ► The NLO response of the systems was dominated by strong nonlinear refraction. The nonlinear optical response of a series of azo-containing side-chain polymers is investigated using Z-scan technique, employing 35ps and 4ns laser pulses, at 532 nm. The systems were found to exhibit strong nonlinear optical response, dominated by nonlinear refraction. In all cases, the nonlinear absorption and refraction have been determined and are compared with those of disperse red 1 considered as reference. The corresponding third-order susceptibilities χ(3) were determined to be as large as 10−7 and 10−5esu under ps and ns laser excitation, respectively. Finally, the results are discussed and compared with other reported data.