Thermally induced relaxation and recovery of the macroscopic orientation in a side-chain liquid crystalline polyacrylate

✍ Scribed by Guoxiong Yuan; Yue Zhao

• Publisher: John Wiley and Sons
• Year: 1994
• Tongue: English
• Weight: 437 KB
• Volume: 195
• Category: Article
• ISSN: 1022-1352
• DOI: 10.1002/macp.1994.021950924

✦ Synopsis

Abstract

Thermal relaxation behavior of a mechanically induced macroscopic orientation of the mesogenic groups in a side‐chain liquid crystalline polyacrylate was investigated using timedependent polarized infrared spectroscopy. It was found that a complete relaxation occurred only at temperatures in the nematic to isotropic transition region, and that, more interestingly, the completely relaxed macroscopic orientation was recoverable by cooling the sample to its nematic state. This thermally induced relaxation and recovery of the macroscopic orientation was reversible upon repeated temperature changing cycles over an aging time of more than five hours. Moreover, the level of the orientation recovery was found to be sensitive to the recovery and relaxation temperatures and to the annealing duration at the relaxation temperature before cooling. A tentative interpretation is proposed for this orientation recovery.