Synthesis and characterization of Y‐type polymers for second‐order nonlinear optical applications |
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| Authors: | Balakrishna Kolli Sarada P Mishra Akshaya K Palai Tapan Kanai M P Joshi S Raj Mohan T S Dhami L M Kukreja A B Samui |
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| Institution: | 1. Polymer Science and Technology Centre, Naval Materials Research Laboratory, Shil‐Badlapur Road, Ambernath, Thane 421506, Maharashtra, India;2. Laser Materials Processing Division, Raja Ramanna Centre for Advanced Technology, Indore 452013, Madhya Pradesh, India |
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| Abstract: | A series of dicyanomethylene‐substituted polymers having Y‐type molecular architecture were synthesized by Knoevenagel condensation reaction. The polymers were found to be soluble in organic solvents like tetrahydrofuran and chloroform. From gel permeation chromatography, the molecular weights of the polymers were found to be in the range of 15,300–33,800 g/mol. Thermal analysis showed that the polymers were stable up to 350 °C with glass transition temperature (Tg) in the range of 129–212 °C. These polymers were found to form good optical quality films. The order parameter was calculated to be in the range of 0.01–0.48. Atomic force microscopy indicated prominent morphology changes due to alignment of dipoles after poling. By using Nd:YAG laser of 1064 nm, angular dependence and temperature dependence of second‐harmonic generation intensity were investigated. The geometry optimization, shape of polymers, and restricted torsion angle between acceptor and donor substituents (push–pull system) were calculated. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 |
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| Keywords: | atomic force microscopy (AFM) corona poling differential scanning calorimetry (DSC) dipole alignment glass transition NLO order parameter polymers relaxation second‐harmonic generation UV– vis spectroscopy |
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