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We present a nondestructive experimental technique for the determination of the lateral distribution of the polar order in second-order nonlinear optical thin films. The sample, which consists of a poled polymer film is scanned through the focus of an infrared laser beam in a second-harmonic generation setup and the second-harmonic intensity is monitored stepwise. In combination with a conventional electro-optic (EO) characterization it is possible to create an EO-coefficient map of the sample. The resolution of this mapping technique can be significantly increased by using high numerical aperture microscope optics for the illumination of the poled polymer. This method, for instance, allows the evaluation of poling inhomogeneities due to high-field poling and field distortions at the edges of poling electrodes.

We present an experimental technique for nondestructive measurement of the glass transition temperature (Tg) of thin nonlinear optical (NLO) polymer films by attenuated total reflection spectroscopy. At Tg the thermal expansion coefficient and temperature dependence of the refractive index ∂n/∂T change discontinuously. This change can be detected with high sensitivity by recording thickness and refractive index of a polymer waveguide coated on a glass/gold substrate as a function of temperature. Measurements were made on various high Tg NLO polymers (Tg up to 170 °C). The resulting Tg values are compared with those determined by differential scanning calorimetry of the bulk material.

The chemical and physical properties of photobleached nonlinear optical (NLO)‐polymethacrylates were studied in order to investigate photobleaching mechanisms. We have shown by three key measurement techniques (infrared‐spectroscopy, mass spectrometry, and gel permeation chromatography) that the predominant bleaching process is an irreversible decomposition of the NLO moieties accompanied by a broadening of the polymer molecular weight distribution. The quantum yield of the chromophore degradation determined by the evaluation of the bleaching kinetics fit is in agreement with typical data from comparable chromophores. It was found that bleaching causes an increase in surface roughness of NLO‐polymer films, causing an increase in waveguide loss. Smoothing of the film surface by an annealing step leads to a lowering of bleaching induced waveguide loss.