Annual Report 2012 - Latvijas Universitātes Cietvielu fizikas institūts

Collaboration
Latvia:
Lithuania:
• Riga Technical University;
• Institute of Organic Synthesis;
• Institute of Physical Energetics;
• Daugavpils University.
• Vilnius University (Prof. S. Jursenas);
• Kauņas universitāte (Prof. J. V. Grazulevicius);
• Center for Physical Sciences and Technology (Prof. L. Valkunas un Prof. V.
Gulbinas).
Taiwan: National Sun Yat-sen Universty (Dr. Li-Yin Chen).
France: Institut des Nanosciences de Paris (Prof. N. Witkowski).
England: Nottingham University (Prof. S. Woodward).
Germany: Julius-Maximilians Universitaet Wuerzburg (Prof. J. Pflaum).
Bulgaria: Institute of Organic Chemistry, Bulgarian Academy of Sciences (Prof. V.
Dimitrov).
Moldova: Universitatea Tehnica a Moldovei (Prof. A. Casian).
Main results
TRIPHENYL MOIETIES AS BUILDING BLOCKS FOR OBTAINING
MOLECULAR GLASSES WITH NONLINEAR OPTICAL ACTIVITY
Kaspars Traskovskis, a Igors Mihailovs, a,b Andrejs Tokmakovs, b Andrejs Jurgis, b
Valdis Kokars a and Martins Rutkis b
The incorporation of trityl and triphenylsilyl groups into low molecular weight
molecules allows obtaining stable molecular glasses. Series of materials based on N-
phenyldiethanolamine core were synthesized bearing different azobenzenes and
benzylydene-1,3-indandione as active chromophores. Molecular hyperpolarizability of
synthesized compounds was calculated by Restricted Hartree–Fock method with basis 6-
31G and measured in solutions by hyper-Rayleight scattering. Non-linear optical (NLO)
activity of thin glassy films was confirmed after corona polling procedure. Thermal
sustainability of NLO response by up to 85° C was achieved. Quantum chemical
calculations of compounds revealed increased sterical bulk and conformational freedom
of triphenylsilyl moiety. While the presence of triphenylsilyl group results in more
stable glasses and increased material nonlinearity, in the case of trityl groups, measured
glass transition temperatures are higher.
In this paper, we have presented a new structural design of low molecular organic
glasses suitable for photonics studies. Synthesized triaryl functionalized N-
phenyldiethanolamine derivatives has shown excellent solubility in non-polar organic
solvents and are able to form good optical quality glassy films without a mixing in a
polymer matrix. Stability of the films was sufficient to undergo corona discharge poling
at the elevated temperatures, making the materials NLO active.
112