Structure and crystallization of SiO2 and B2O3 doped lithium disilicate glasses from theory and experiment

TL;DR

This study combines theoretical simulations and experimental methods to analyze how SiO2 and B2O3 dopants influence the structure, crystallization, and properties of lithium disilicate glasses, revealing dopant-specific effects on viscosity and crystal growth.

Contribution

It provides the first synthesis and characterization of SiO2 and B2O3 doped lithium disilicate solid solutions, integrating density functional theory with experimental crystallization analysis.

Findings

SiO2 increases glass viscosity and decreases crystal growth velocity.

B2O3 reduces both viscosity and crystal growth velocity.

Dopant effects are linked to changes in the glass matrix composition during crystallization.

Abstract

Solid solutions of SiO2 and B2O3 in Li2O 2SiO2 are synthesized and characterized for the first time. Their structure and crystallization mechanisms are investigated employing a combination of simulations at the density functional theory level and experiments on the crystallization of SiO2 and B2O3 doped lithium disilicate glasses. The remarkable agreement of calculated and experimentally determined cell parameters reveals the preferential, kinetically controlled incorporation of [SiO4] and [BO4] at the Li+ lattice sites of the Li2O 2SiO2 crystal structure. While the addition of SiO2 increases the glass viscosity resulting in lower crystal growth velocities, glasses containing B2O3 show a reduction of both viscosities and crystal growth velocities. These observations could be rationalized by a change of the chemical composition of the glass matrix surrounding the precipitated crystal phase during the course of crystallization, which leads to a deceleration of the attachment of building units required for further crystal growth at the liquid-crystal interface.