Dielectric and thermal properties of organic ferroelectric (R)-3-quinuclidinol in porous glass

The results of studies of the dielectric constant ε′ and the DTA signal of a new organic ferroelectric (R)-3-quinuclidinol (C7H13NO), embedded in porous glasses with an average pore size of 100 nm, are presented. The phase transition was found to shift to low temperatures by 3 K upon heating and 6 K upon cooling, in comparison with bulk (R)-3-quinuclidinol. A decrease in the phase transition temperature in composites with (R)-3-quinuclidinol nanoparticles is consistent with theoretical models of the influence of size effects on the structural phase transition.

Effect of P2O5 Impurities and Fluoride Ions on The Rheological Properties of Porous Glasses and Bismuth-Containing Composites Based on Them

The results of a study of the rheological properties (shrinkage on heating, viscosity) of porous glasses (PGs) obtained as a result of through acid leaching of two-phase sodium borosilicate glass doped with small additives of P2O5 and fluoride ions, as well as bismuth-containing PGs and quartzoid glasses based on them, depending on the temperature of the heat treatment of the PG and in comparison with the characteristics of the samples obtained from sodium borosilicate glass without additives, are presented. It is found that doping glass with the indicated impurities leads to a decrease in the thermal resistance of the obtained PGs and bismuth-containing PGs. The introduction of bismuth nitrate into PG in the case of the low-temperature treatment (at 120°C) lowers the temperature for the same viscosity values of quartzoid glasses by 15–20°C, in contrast to samples without additives, as well as from higher-temperature treatment (at 650°C) PGs with additives.

Mechanical Properties and Pore Size Distribution in Athermal Porous Glasses

In this paper, we study the mechanical properties and pore structure in a three-dimensional molecular dynamics model of porous glass under athermal quasistatic shear. The vitreous samples are prepared by...