Journal article
Cone motion viscosity and optical second harmonic generation of ferroelectric liquid crystalline dendrimers
No matching items found.
Research Areas
No matching items found.
Publication Details
Author list: Jonas, Örtegren
Publication year: 2001
Start page: 861
End page: 868
Number of pages: 8
ISSN: 0267-8292
Abstract
We report second harmonic generation in a ferroelectric liquid crystalline trimer and ferroelectric liquid crystalline dendrimers of first, second and third generation. Thin cells were filled with the compounds by capillary forces at elevated temperature, and cooled from the surface stabilized ferroelectric state to below the glass transition temperature, while kept in an electric field. The cone motion viscosity and the threshold electric field for unwinding of the helix axis of the chiral tilted smectic mesophases were studied separately at elevated temperature, and these data were used to optimize the preparation of the films. The measured response time was between 0.3 and 3ms, which corresponds to a cone motion viscosity between 0.5 and 50 Pa s. Second harmonic generation was studied both at elevated temperature with an electric field and at room temperature with and without electric field. The first generation dendrimer exhibited a strong increase in the second order non-linear optical response with time at room temperature. The d23-coefficient of this dendrimer was approximately four times larger than for the other macromolecules and was 0.045 pm/V. The relatively large d-coe cient of the first generation dendrimer is ascribed to crystallization, which improved the orientation of the molecular dipoles.
Projects
No matching items found.
Keywords
No matching items found.
Documents
No matching items found.