Photochemical isomerization of thioindigo derivatives embedded in poly(methyl methacrylate)

Synthesis and optical properties of photochromic perinaphthothioindigo

“…Although three compounds could conceivably be formed from these two fragments, two symmetric and one asymmetric, we only see the asymmetric (1,2-naphtho)(1,8-naphtho)thioindigo isomer under our product isolation conditions. Our visible spectrum agrees with that reported by Veniaminov and Laskov [9] for PNT (structures A&B in Fig. 1).…”

“…The form studied here, (1,2-naphtho)(1,8-naphtho)thioindigo, has an absorption spectrum which is in agreement with a compound called PNT by several groups [5,6,9]. Veniaminov and Lashkov [9] report that the trans form of PNT (Fig. 1A) has a peak at 592 nm and the cis form (Fig.…”

“…Little information is available in the literature regarding synthesis of the perinaphthothioindigos: typically reference is made to a paper by HarleyMason and Mann [11], which does not provide specific details on this synthesis. The form studied here, (1,2-naphtho)(1,8-naphtho)thioindigo, has an absorption spectrum which is in agreement with a compound called PNT by several groups [5,6,9]. Veniaminov and Lashkov [9] report that the trans form of PNT (Fig.…”

“…Thus, even with monochromatic light incident on the sample at the maximum absorption of either form, only photostationary states containing a mixture of the two isomers could be prepared. Perinaphthothioindigo dyes have been reported by several groups [3][4][5][6][7][8][9][10]; the absorption spectra and properties differ among the dyes. Little information is available in the literature regarding synthesis of the perinaphthothioindigos: typically reference is made to a paper by HarleyMason and Mann [11], which does not provide specific details on this synthesis.…”

Photochemical kinetics for holographic grating formation in phenanthrenequinone doped poly (methyl methacrylate) photopolymer

“…( 5), if the grating is formed in 30 minutes, in order to make a diffusing distance of 10 −2 µm (1% of grating spacing in this study), the diffusion coefficient of PQ molecules must be in the order of 10 −19 m 2 /s. Veniaminov et al [17] have obtained the diffusion coefficient by holography methods and have found that it is related to the environmental temperature. The diffusion coefficient is in the order of 10 −21 m 2 /s at 20 • C, and it increases to 10 −19 m 2 /s in the temperature range from 50 • C to 75 • C. Therefore, it is reasonable to ignore the diffusion process of PQ molecules in our experiment environmental (room temperature).…”