Structure, dielectric property and viscosity of alkali-free boroaluminosilicate glasses with the substitution of Al2O3 for SiO2

摘要

In this work, the effects of Al2O3/SiO2 ratio on the structure, dielectric property and viscosity of alkali-free boroaluminosilicate glasses were investigated by FTIR spectroscopy, density, impedance analyzer and rotating crucible viscometer. The FTIR analysis showed that the substitution of Al2O3 for SiO2 had little effect on the conversion between [BO3] and [BO4]. The lower-leveled tetrahedral units Q(1) and Q(2) changed into Q(3) and Q(4), which led to the aggregation of glass network structure. With the increase of Al2O3 SiO2 ratio, both the measured density and calculated density of glass samples monotonically increased. While the molar volume decreased from 27.29 to 26.80 cm(3) /mol, which could also indicate a denser glass network structure. When the Al2O3/SiO2 ratio increased, the dielectric constant and loss decreased from 6.2 to 5.0 and 0.00396 to 0.00176, respectively. Meanwhile, the melting temperature and viscosity of the glasses increased, which were consistent with the variation of glass network structure.