Dresden 2003 – wissenschaftliches Programm

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CPP: Chemische Physik und Polymerphysik

CPP 5: Elektronische Eigenschaften von Polymeren

CPP 5.1: Vortrag

Montag, 24. März 2003, 17:00–17:15, ZEU/160

Second harmonic generation of light in No-dqclassicalNo-dq ferroelectric and novel No-dqferroelectretNo-dq polymers — •Ingrid Graz, Michael Lindner, Simona Bauer-Gogonea, and Siegfried Bauer — Johannes-Kepler University, Soft Matter Physics, Altenberger Str. 69, Linz, Austria

Second harmonic generation (SHG) of light is widely employed in the study of amorphous poled polymers for photonics. Much less efforts have been dedicated to the investigation of other classes of polymers by means of nonlinear optical techniques, though the potential of the optical methods has a much broader basis than the investigation of photonic materials. Here we apply SHG to the investigation of ferroelectric polymers, where the SH light stems from noncentrosymmetrically oriented dipolar groups in the polymer chain. SHG can be used to monitor ferroelectric hysteresis loops, without being affected by spurious signals from nonlinear conductivity. Traditionally, it is thought that SHG can be observed only in noncentrosymmetric polar materials. Here we will also demonstrate that SHG can be observed in nonpolar cellular polymer electrets, internally charged by dielectric barrier microdischarges. The close analogy to ferroelectric materials is outlined, therefore justifying the introduction of the term No-dqferroelectretNo-dq for this novel class of materials.