Effect of sub-Tg relaxations on chromophore reorientation in corona-poled polymers

✍ Scribed by Shane C. Brower; L. Michael Hayden

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 290 KB
• Volume: 36
• Category: Article
• ISSN: 0887-6266
• DOI: 10.1002/(sici)1099-0488(19980430)36:6<1013::aid-polb10>3.0.co;2-9

✦ Synopsis

Activation volumes for chromophore reorientation were measured for a series of guest-host polymeric materials, indicating a significant coupling between chromophore motion and the glassy a and b relaxation dynamics of the polymer host. The specific systems studied were formed by individually dissolving N,N-dimethyl-p-nitroaniline (DpNA), 4-(dimethylamino)-4-nitrotolane (DMANT), 4-(diethylamino)-4-nitrotolane (DEANT), and 1-((4-(dimethylamino)phenyl)ethynyl)-4-((4-nitrophenyl)ethynyl)benzene (DMAPEANT) in poly(methyl methacrylate) (PMMA), poly(ethyl methacrylate) (PEMA), and poly(isobutyl methacrylate) (PiBMA). In each of these systems, the isothermal, sub-T g decay of the second-order optical susceptibility x (2) was monitored as a function of pressure using second harmonic generation. In each system, the observed decay of x (2) was represented by a stretched exponential equation from which the decay time t 0 and decay distribution width b KWW were determined. For each dopant molecule, the decrease in activation volume with the increasing size of the polymer host's alkyl side group and the pressure dependence of b KWW were indicative of partial coupling between chromophore rotation and the glassy b relaxation dynamics of the polymer host.