The effect of high temperature on the infrared spectra of fully cured PMDA/ODA polyimide is discussed. Changes in some bands can be explained by Boltzmann effects on the distribution of excited states. Other bands, in particular the 1780-cm−1 band that is often used for cure measurements, change in ways that cannot be related to Boltzmann's equation. These band position and intensity changes are explained as configurational changes occurring during heating. Determination of correction factors for integrated peak areas from spectra taken at elevated temperature are discussed.

Abstractm‐phenyl benzoate end‐capped pre‐polybenzoxazole oligomer and a 3,4‐diaminobenzene endcapped pre‐polybenzimidazole were synthesized. These functionalized oligomers were then condensed to give a polybenzoxazole‐polybenzimidazole segmented block copolymer. The functionalized oligomers were characterized by proton NMR, diffuse reflectance FTIR, and thermal gravimetric analysis. The final block copolymer was characterized by diffuse reflectance FTIR and thermal gravimetric analysis.