Effect of Molecular Weight on Photoinduced Birefringence in a Chiral Liquid Crystalline Azodye Polymer

✍ Scribed by Mikhail Kozlovsky; Vladimir V. Lazarev

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 186 KB
• Volume: 27
• Category: Article
• ISSN: 1022-1336
• DOI: 10.1002/marc.200500669

✦ Synopsis

Abstract

Summary: The evolution of the photoinduced birefringence in thin films of narrow polymer fractions is studied and compared with the behavior of the non‐fractionated polymer. The Δ__n__~ind~ value decreases by increasing the degree of polymerization ($\overline {DP}$) within the oligomeric range but becomes independent of molecular weight starting from a $\overline {DP}$ of ≈70. Thermal pretreatment of the films results in higher photoinduced birefringence. The films show good stability of the photorecording.

Birefringence induced after 10 min, Δ__n__~ind~(600) and its growth rate at the same moment versus molecular weight.

magnified imageBirefringence induced after 10 min, Δ__n__~ind~(600) and its growth rate at the same moment versus molecular weight.