Detection of Crosslink Formation by 2 + 2 Photocycloaddition in Poly (Vinyl Cinnamate) by 13C Solid-State NMR
Abstract
Poly (vinyl cinnamate), PVCN, is one of the more important polymers used in NLO research. It is frequently used as a host polymer into which suitable dyes are introduced, especially those with limited solubilities in other polymers. During the poling process, the polymer may be irradiated with UV light to yield a material with superior SHG retention and reduced solubility. This is frequently. This is frequently assumed to be due to photocrosslinking reactions between cinnamoyl groups in different chains or alternatively between cinnamoyl groups and NLO dye molecules with suitable structures. The mechanism of this crosslinking is proposed to be 2 + 2 cycloaddition of the olefinic groups to yield four-membered-ring crosslink sites. Although this mechanism is appealing in that it is consistent with well characterized reactions in solution, experimental evidence for this important reaction in NLO polymers has been lacking, and its acceptance has not been universal.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 13, 1994
- Accession Number
- ADA281955
Entities
People
- James F. Haw
- Timothy W. Skloss
Organizations
- Texas A&M University