Polarization-selective photochromic reaction in glassy polymers: effects of local relaxation processes of polymer matrix

Abstract

The extent to which the intramolecular heterophotodimerization of the photochromic molecule 9-(hydroxymethyl)-10-[(naphthylmethoxy)methyl]anthracene (HNMA), incorporated into a poly-(methyl methacrylate) (PMMA) matrix, is induced by irradiation with linearly polarized light was investigated. The degree of photodimerization was evaluated by using the polarization-induced efficiency parameter, 7, which is defined as the normalized difference between the two components of dichroic absorbance. It was found that 7 is affected by both the @-relaxation process and the glass transition temperature, Tg (T, = 103 "C) of the PMMA matrix. As irradiation time increases, 7 increases and reaches a limiting value, qmar, of ca. 6% at temperatures of around 40 "C. These results indicate that, by utilizing the selective induction of the intramolecular heterophotodimerization of HNMA, which occurs upon excitation with polarized light, it is possible to generate and control the spatial distribution of the refractive index of glassy polymer films, thereby making them potentially useful as optoelectronic materials for wave guiding or light modulation.

Molecularly Imprinted Anisotropic Polymer Monoliths

“…Tran-Cong et al, for example, studied an intramolecular photodimerization of 9-(hydroxymethyl)-10-[(naphthylmethoxy)methyl]anthracene in a uniaxially oriented PMMA film. [56][57][58] Other examples of assemblies of oriented molecules are liquid crystals, which without any "post-functionalization" are oriented owing to their inherent geometry. 60 In this paper we have described an entirely novel way of preparing selective, anisotropic polymer networks by the molecular imprinting of polymers and subsequent irradiation of the template molecules with linearly polarized light.…”

“…The degree of anisotropy introduced into the polymer network, although small, agrees well with literature data obtained from photoreactions of small molecules entrapped in aligned polymer matrices. [56][57][58][59] The development of chemical sensors based on these results now appears feasible in principle, but sensitivity would be low with the small degrees of anisotropy so far achieved. …”

Effects of Physical Aging on Polarization-Induced Photodimerization in the Glassy Region of Poly(methyl methacrylate)

“…14 The chemical structure of HNMA and its intramolecular photodimerization are shown in Figure 1. The concentration of HNMA in PMMA was adjusted to 2.5-3.0 x 10-3 M by solvent casting.…”

Copolymers of 4-nitrophenyl methacrylate with styrene: Synthesis, characterization, and reactivity ratios

“…[3][4][5] The incorporation of 9-(hydroxy methyl)-10-[naphthyl(methyl)]anthracene into poly(methyl methacrylate) (PMMA) results in a glass polymer film that can be used as an optoelectronic material. 6 The distribution of homopolymers in a symmetric block copolymer like poly(styrene-b-methyl methacrylate) was determined from neutron reflectivity studies. 7 The intramolecular structure of styrenemethacrylate (STY-MA) copolymers was evaluated by 1 H-and 13 C-NMR studies and also by 2D-NMR COLOC experiments.…”