Structure-mediated dielectric response in boroaluminosilicate glasses: A molecular dynamics perspective

CY Chen and R Yang and MY Yang and WZ Wang and QC Jia and Q Zu and SX Huang and Y Zhang and HD Zeng, CERAMICS INTERNATIONAL, 51, 33194-33203 (2025).

DOI: 10.1016/j.ceramint.2025.05.052

Boroaluminosilicate glass is a critical material for low-dielectric glass fibers used in advanced electronics. In this work, the composition-structure-property relationships in X%Al2O3-(1-X%) (62.5SiO(2)-22.7B(2)O(3)-4.5-MgO-8.0CaO-2.3Li(2)O) (mol%) from metaluminous to peraluminous compositions combined with molecular dynamics simulation were investigated. Our results reveal a pronounced change in thermodynamics around Al2O3/Li2O + CaO + MgO ratio<1. The structure of thermodynamic changes originates from changes in network connectivity and non-bridging oxygen. Furthermore, the complex structural speciation in boroaluminosilicate glasses results in a nonlinear variation in dielectric loss, while the dielectric constant shows a linear dependency on Al2O3 content. The charge compensation for AlO4, along with the presence of AlO5 and AlO6 enhance oxygen polarizability, leading to a continuous increase in the dielectric constant. Dielectric loss correlates with conductivity, as AlO4 units facilitate the migration of network modifiers, whereas AlO5 and AlO6 occupy voids in the glass network, hindering the migration and reducing dielectric loss. This work provides a valuable strategy for optimizing dielectric and thermal properties in electronic packaging substrates and other applications.

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