• Schab-Balcerzak, Ewa
• Konieczkowska, Jolanta
• Kotowicz, Sonia
• Kozanecka-Szmigiel, Anna
• Neugebauer, Dorota
• Mazur, Aleksy

Abstract

<jats:title>Abstract</jats:title><jats:p>A new azo polymer containing photoisomerizable azo pyridine functionalities was synthesized via Mitsunobu reaction of 4-(4-hydroxyphenylazo)pyridine with poly(2-hydroxyethyl methacrylate-<jats:italic>co</jats:italic>-methyl methacrylate) (p(HEMA-<jats:italic>co</jats:italic>-MMA)) for creating new photochromic materials. The resulting polymer with azo pyridine side groups was characterized for structural, thermal, and optical properties. UV–vis, <jats:sup>1</jats:sup>H NMR and IR spectroscopies confirmed that all hydroxyl groups in p(HEMA-<jats:italic>co</jats:italic>-MMA) were substituted with azo dye. The obtained azo copolymer exhibited high thermal stability (around 240 °C) and a glass transition temperature (113 °C), promising for applications. The <jats:italic>trans</jats:italic>-to-<jats:italic>cis</jats:italic> isomerization upon UV irradiation and the thermal back reaction of the azo chromophore in the copolymer in the solid state was studied. A photostationary state with 50% content of <jats:italic>cis</jats:italic>-isomers upon 6 min of UV irradiation was reached, and during 48 h dark relaxation at ambient temperature, all <jats:italic>cis</jats:italic>-isomers converted to the <jats:italic>trans</jats:italic> form. Additionally, the possibility of efficient photogeneration of surface relief gratings with high amplitude of azo copolymer surface modulation was demonstrated.</jats:p>

Topics

• surface
• glass
• glass
• glass transition temperature
• copolymer
• Nuclear Magnetic Resonance spectroscopy
• chemical ionisation