Rigid glassy matrix

When 3-methylpentane was used as a matrix molecule, instead of MeTHF, however, no such isomerization reaction was observed. This could be due to the nature of 3-methylpentane, which gives a nonpolar and soft matrix at 77 K. MeTHF is a polar molecule that forms a rigid glassy matrix at 77 K. The electrons generated by ionizing irradiation are stabilized in MeTHF. This polar and rigid nature of the MeTHF matrix can be responsible for the phenomenon Both anion radicals are thermally stable, so the photoisomerization reaction shown was observed. 

The low temperature luminescence spectra of the title compounds in poly(methyl methacrylate) (PMMA) are shown in Fig. 4. In addition to the solvatochromic effect the MLCT luminescence bands show a pronounced rigidochromic effect. However, not only the emission energies, but also the band shapes change when the low viscosity solvents are replaced by a rigid glassy matrix. 

In view of these results for binary glasses composed of molecules with different masses respectively different Tg, one may speculate that the isotropic reorientation of the small molecules results from translational diffusion in an essentially rigid glassy matrix formed by the large molecules, i.e., the diffusional process may be probed by 2H NMR via rotational-translational coupling.183 Finally, we note that the stimulated-echo technique was also applied to study the main relaxation in... 

Miller. J.R. Beitz. J.V. Long-range transfer of positive charge between dopant molecules in a rigid glassy matrix. J. Chem. Phys. 1981, 74. 6746. 

The life-time of the ionic intermediates in the liquid solutions is so short that it is difficult or impossible to observe them directly. One of the convenient ways to overcome this difficulty is to prolong the life-time by freezing the irradiated solution at low temperature. For convenience of measurement, organic substances frozen to a glassy state have been widely used as solvents for the study by means of optical absorption measurement at low temperature. A rigid glass matrix is preferably used also in the ESR study, because the experimental results are readily compared with those obtained by the optical study. 

Copolymers in regions 4 and 6 consist of crystallites in an amorphous, glassy matrix. Since both phases are rigid, the materials are hard, stiff, and rigid. Again, the two phases impart opacity. Nylon 6/6 and nylon 6 are examples of homopolymers in a region below both Tg and Tm at room temperature. 

Glassy polymers with much higher glass transition temperatures and more rigid polymer chains than rubbery polymers have been extensively used as the continuous polymer matrices in the zeolite/polymer mixed-matrix membranes. Typical glassy polymers in the mixed-matrix membranes include cellulose acetate, polysul-fone, polyethersulfone, polyimides, polyetherimides, polyvinyl alcohol, Nafion , poly(4-methyl-2-pentyne), etc. 

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