We have investigated the orientational dynamics of the ternary mixture of propyl, pentyl and heptyl cyano-cyclohexyls (ZLI-1167) in the isotropic phase over a wide temperature range (372-453 K) by means of transient optical Kerr effect spectroscopy. The orientational dynamics of ZLI-1167 isotropic phase shows a complex relaxation pattern where several dynamical processes take place. We substantially observed three time scales of relaxation: fast (from hundreds of fsec to few psec), intermediate (from tens to hundreds of psec) and slow (from hundreds of psec to few nsec). The slow orientational relaxation shows a temperature dependence characterized by strong pre-transitional effects. The critical slowing down of these relaxation times can be correctly interpreted by Landau-de Gennes theory. The fast and intermediate decay times show a different temperature dependence without any observable pre-transitional effects. We suggest an interpretation of the experimental results in term of averaged single molecule dynamics and collective dynamics

Orientational Dynamics in the isotropic phase of a nematic mixture: Subpicosecond time resolved optical Kerr effect experiments on ZLI-1167 liquid crystal / R. Torre; M. Ricci; G. Saielli; P. Bartolini; R. Righini. - In: MOLECULAR CRYSTALS AND LIQUID CRYSTALS. - ISSN 1563-5287. - STAMPA. - 262:(1995), pp. 391-402.

Orientational Dynamics in the isotropic phase of a nematic mixture: Subpicosecond time resolved optical Kerr effect experiments on ZLI-1167 liquid crystal

TORRE, RENATO;RICCI, MARILENA;BARTOLINI, PAOLO;RIGHINI, ROBERTO
1995

Abstract

We have investigated the orientational dynamics of the ternary mixture of propyl, pentyl and heptyl cyano-cyclohexyls (ZLI-1167) in the isotropic phase over a wide temperature range (372-453 K) by means of transient optical Kerr effect spectroscopy. The orientational dynamics of ZLI-1167 isotropic phase shows a complex relaxation pattern where several dynamical processes take place. We substantially observed three time scales of relaxation: fast (from hundreds of fsec to few psec), intermediate (from tens to hundreds of psec) and slow (from hundreds of psec to few nsec). The slow orientational relaxation shows a temperature dependence characterized by strong pre-transitional effects. The critical slowing down of these relaxation times can be correctly interpreted by Landau-de Gennes theory. The fast and intermediate decay times show a different temperature dependence without any observable pre-transitional effects. We suggest an interpretation of the experimental results in term of averaged single molecule dynamics and collective dynamics
1995
262
391
402
R. Torre; M. Ricci; G. Saielli; P. Bartolini; R. Righini
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Utilizza questo identificatore per citare o creare un link a questa risorsa: https://hdl.handle.net/2158/687221
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