We describe the one-pot syntheses of an azobenzene- and pyridine-functionalized benzoxazine monomer (PAPBZ) and a main chain-type polybenzoxazine (BAPBZ) through Mannich condensations of a diamino- and azobenzene-containing pyridine derivative (azo-pyridine-2NH₂), paraformaldehyde, and either phenol or bisphenol in a mixture of toluene and EtOH. Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopy confirmed the chemical structures of the benzoxazine monomer and polymer. The thermal curing behavior and stability of these benzoxazines were monitored using differential scanning calorimetry, FTIR spectroscopy, and thermogravimetric analysis; the PAPBZ monomer underwent complete ring-opening polymerization to form its polybenzoxazine, while the BAPBZ polymer also underwent thermal curing to give a high-density cross-linked polybenzoxazine. Because of the photoresponsive azobenzene units in the benzoxazine monomer and in the main chain of the polybenzoxazine, these materials exhibited photoresponsivity through reversible photoinduced trans-to-cis isomerization under UV irradiation. The degrees of isomerization of PAPBZ and BAPBZ were 19.3 and 13.9%, respectively. In addition, we used these materials to fabricate surface relief gratings exhibiting interference patterns with tunable long-range order. Accordingly, such azobenzene- and pyridine-functionalized benzoxazines appear to have applicability within optical devices and optical storage media.

中文翻译：

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基于吡啶官能化苯并恶嗪作为表面浮雕光栅的光响应性偶氮苯材料

我们描述了一锅合成的偶氮苯和吡啶官能化的苯并恶嗪单体（PAPBZ）和主链型聚苯并恶嗪（BAPBZ）通过含二氨基和偶氮苯的吡啶衍生物（偶氮吡啶2NH ₂）的曼尼希缩合反应），低聚甲醛以及甲苯和EtOH的混合物中的苯酚或双酚。傅里叶变换红外（FTIR）和核磁共振（NMR）光谱证实了苯并恶嗪单体和聚合物的化学结构。使用差示扫描量热法，FTIR光谱和热重分析法监测这些苯并恶嗪的热固化行为和稳定性。PAPBZ单体进行完全的开环聚合反应以形成其聚苯并恶嗪，而BAPBZ聚合物也进行热固化以得到高密度的交联聚苯并恶嗪。由于苯并恶嗪单体和聚苯并恶嗪的主链中具有光响应性的偶氮苯单元，这些材料通过在紫外线照射下可逆的光诱导的反式-顺式异构化表现出光响应性。PAPBZ和BAPBZ的异构化程度分别为19.3％和13.9％。此外，我们使用这些材料来制造表面起伏光栅，该光栅表现出具有可调节的远距离阶跃干涉图案。因此，这种偶氮苯和吡啶官能化的苯并恶嗪似乎在光学器件和光学存储介质中具有适用性。