The Network structure and viscoelastical-rheological properties of multicomponent aluminosilicate glass

In this work, we investigate the structure and viscoelastic rheological properties of multicomponent aluminosilicate glasses with Al/(Si+Al) ratios ranging from 0.37 to 0.52. It is found that an increase in the Al/(Si+Al) ratio enhances the connectivity of the glass network, leading to the enhancement of glass transition temperature T g (661.8–690.2 °C), softening temperature T d (725.5–744.9 °C), and high-temperature viscous activation energy ( VAE ) (165.02–190.13 kJ/mol). With increasing Al/(Si+Al) ratio, the coefficient of thermal expansion ( CTE ) first decreases and then increases, reaching a minimum of 7.196 × 10 –6 1/K when the Al/(Si+Al) ratio is ∼0.45. Meanwhile, the fragility index ( m ) and operational temperature range reach the maximum and minimum values of 36.97 and 232.7 °C, respectively. Viscoelastic properties of glass show a strongly dependent on the Al/(Si+Al) ratios. At Al/(Si+Al) ratios of 0.37, 0.41, and 0.49, both the loss angle tan θ and relaxation time decrease and then increase, with values of 0.41, 0.34, and 3.17, and 0.0624, 0.0516, and 0.2014 s, respectively. The variations in the loss angle and relaxation time suggest that the network connectivity alone does not fully account for the viscoelastic properties of glass.