Microscopic structure of three types of porous glasses with the average pore diameter of 5, 7 and 140 nm obtained by chemical etching was studied by neutron diffraction. The analysis of diffraction patterns has shown that in these glasses, besides an amorphous phase forming a weakly structured background, there are microscopic crystalline inclusions of sassolite with a diffraction size of 26š3 nm and of ?-quartz with a characteristic size of 6š1 nm. Microcrystalline inclusions sizes do not depend on the average pore size diameter. It is shown that in these samples a tridymite phase does not make a significant contribution to observed scattering and a relative sassolite contribution decreases substantially with the average pore size increasing from 5 to 140 nm.
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In the present contribution we have studied the dielectric properties of two-phase sodium borosilicate glasses doped by iron oxide and of porous media based on them. The temperature dependences of dielectric permittivity and conductivity for all samples have been obtained, and the impedance spectroscopy analysis for porous magnetic glasses has been done. The obtained data allow us to estimate the values of activation energies for porous samples.
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A summarizing of the results of complex study of pore morphology of porous glasses has been carried out taking into consideration the dissolved secondary silica state in the systems alkali borosilicate glass - a leaching solution. An influence of the composition and phase structure of an initial glass, and their leaching conditions, on the colloid-chemical characteristics of the porous glasses has been shown. The polymodal micro porous substructure and meso porous one, the size and a form of the pores and secondary silica particles as well as the fractal dimensions of their aggregates, the coefficients of structural resistance and tortuosity of the pores has been discussed.
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The comparative research of the structure of the phase-separated glasses of sodium borosilicate system with/without the additives of fluorides and phosphorus oxide, as well as of the porous glasses received from the two-phase glasses were carried out with the help of the methods of electronic microscopy and X-ray phase analysis. It was founded out the distinctions of phase morphology of the two-phase glasses which contain or not a fluorine and phosphorus. Inside the phase-separated glasses with the additives, the microcrystalline formations which are kept inside the porous glasses were detected. An assumption was made that the revealed structure features of the porous glasses can be the reasons for observable differences of their optical properties, namely a light transmittance in the visible region.
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