ACTA

Dynamics and Phase Transitions of 4-Bromobenzylidene-4'-pentyloxyaniline and 4-Bromobenzylidene-4'-hexyloxyaniline as Studied by Dielectric Spectroscopy

N. Osiecka^a, M. Massalska-Arodź^a, Z. Galewski^b, K. Chłędowska^c, S. Wróbel^d, T. Morito^e, Y. Yamamura^e and K. Saito^e
^aThe Henryk Niewodniczański Institute of Nuclear Physics, Polish Academy of Sciences, E. Radzikowskiego 152, 31-342 Kraków, Poland
^bThe Faculty of Chemistry, University of Wrocław, F. Joliot-Curie 14, 50-383 Wrocław, Poland
^cThe Faculty of Mathematics and Applied Physics, Rzeszów University of Technology, al. Powstańców Warszawy 6, 35-959 Rzeszów, Poland
^dInstitute of Physics, Jagiellonian University, W.S. Reymonta 4, 30-059 Kraków, Poland
^eDepartment of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan

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Significant differences in phase sequence and dynamics between 4-bromobenzylidene-4'-pentyloxyaniline (5BBA) and -bromobenzylidene-4'-heksyloxyaniline (6BBA) substances were detected by broadband dielectric spectroscopy. In the smectic A (6BBA), the smectic B (found in both substances) and the smectic E (5BBA) phases the relaxation was ascribed to reorientations of the molecules around the short axes. Slow dynamics detected in the smectic E and in two crystalline phases of 5BBA was ascribed to conformational changes of molecular chains. Coexistence of Cr(I) and Cr(II) conformationally disordered crystal (CONDIS) phases was observed and vitrification of Cr(II) was identified with help of polarizing microscopy.

DOI: 10.12693/APhysPolA.124.913
PACS numbers: 77.84.Nh, 64.70.pp, 64.70.M-, 33.15.Bh