Observation of Pseudo-Photorefractivity in Monolithic Molecular Glass

Asymmetric energy transfer and optical diffraction in novel molecular glass with carbazole moiety

“…3(b). Sato and Ogino et al pointed out the fact that higher glass transition temperature or relatively restricted mobility of the electro-optic moiety is one of the essential points for beam coupling without an external electric field [7]. The distinct color change from light brown to redbrown at illuminated points was observed.…”

“…Recently, it has been reported that the asymmetric two beam coupling was occurred in the unpoled centrosymmetric azo-dye doped silica-gel composites with photosensitizer and photoconductor of carbazole derivative type [5], polymer composites containing hemicyanine dye [6] and monolithic molecular glass with electron acceptor and donor moieties in the molecule [7] without applying external electric field. We reported that PVCz/NPP/Plasticizer/ TNF system gave large optical gain of 224 cm À1 due to asymmetric beam coupling, and high diffraction of ca.…”

Characterization of Pseudo Photorefractive Materials Based on Polyacrylate Containing 9-Oxo-9<i>H</i>-thioxanthene-10,10-dioxide Moiety

“…Zhang et al reported that carbazole based polyphosphazenes with azo-dye moieties exhibited large coupling gains [24,25]. Our group also reported that an amorphous film of asymmetric succinate containing electron accepting 9-oxo-9H-thioxanthene-10,10-dioxide and electron donating 4-amino--nitrostyrene moieties showed an asymmetric energy transfer (coupling gain; 42 cm -1 ) without an external electric field [26]. An asymmetric energy transfer in a 2BC experiment, which is originated from the phase shift between the interference pattern of coherent beams and the spatial modulation of resulting refractive index discriminates PR effect from other phenomena creating gratings of refractive index such as photoisomerization, and photochromism.…”

“…Figure 1 shows the chemical structures of compounds used in this study. Acrylate monomer (THA) and its homopolymer (PTHA) were synthesized as described in previous papers [13,26]. GPC analysis revealed that number average molecular weight and polydispersity index of PTHA were 1.2×10 4 and 3.6, respectively.…”

Photoinduced grating formation in a polymer containing azo-carbazole dyes

“…In these studies, some groups employed azo-dyes such as Disperse Red 1 (DR1), the fact suggests that the extraordinary behavior relates to photoinduced trans-cis isomerization, and succeeding molecular alignment and macroscopic motion, which have been often observed in surface relief formation of azobenzene derivatives [7,8]. However, there have been some exceptions that did not employ azo derivatives [9][10][11]. Recently, Gallego-Gómez et al employed a sol-gel medium similar to that used by Cheben et al, and conducted a detailed investigation for the grating formation and phase movement, leading to a phenomenological explanation by magnitude and direction of Poynting vector [12].…”