We have studied the pore size dependences of association processes for dye molecules incorporated into the matrix of a porous silicate glass. We have determined the structures of the associates of dye molecules as a function of the type of dye, the dye concentration, and the matrix pore sizes. We have established a nonuniform distribution of the complex dye molecules in the porous glass matrix, which is responsible for the higher efficiency of the association processes for the adsorbed molecules compared with alcoholic solutions of these dyes.Introduction. The interest in optical materials based on organic polyatomic molecules adsorbed in porous silicate glasses is due to the possibility of effectively using such materials in quantum electronics and applied optics, especially as active media for solid-state tunable lasers [1,2]. Therefore study of processes of intermolecular interaction between dye molecules in porous silicate glasses is of significant interest. In [3], electronic excitation energy transport processes were studied in such systems, and it was shown that the distribution of interacting dye molecules in porous silicate glasses is fractal. In this case, it was established that the distribution of dye molecules in porous silicate glasses is nonuniform: regions are observed with an elevated concentration of dye molecules. We know that the presence of such regions, with different dye molecule concentrations, should affect processes for which the efficiency of the process depends on the distance between molecules. Such processes include complexation of molecules found in the ground state and association.In this paper, we present the results of a study of the effect of the pore dimensions in porous silicate glasses on the final degree of association of different types of impurity dye molecules (anionic and cationic).The experiment. We used dyes with different charge properties: cationic dyes (rhodamine 6Zh (R6Zh), methylene blue (MB)) and an anionic dye (eosin). The R6Zh and MB molecules have different sizes.The porous silicate glass matrices were represented by samples of sodium borosilicate glass with pores of different sizes. The average pore radius R pore for each series of samples was: 1.3 nm, 1.7 nm, 3.3 nm, and 6.5 nm.The dyes were introduced into the pores by their adsorption from ethanol solutions. The dye concentrations in the original ethanol solutions was increased successively from 1.0⋅10 -6 to 1.4⋅10 -3 mol/L. The absorption spectra were recorded on a Perkin Elmer Lambda 35 spectrophotometer (Germany).Results and discussion. Let us consider processes of association between dye molecules in porous silicate glass. We know that as the dye concentration increases, additional maxima appear in the absorption spectra corresponding to absorption of the associated molecules. We studied the absorption spectra of alcoholic solutions of these dyes and the spectra of molecules adsorbed in the porous glass matrix. The absorption spectra obtained cross at the isosbestic point (i.e., we have a binary mixtur...
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