The fiber spinnability and mixed alkaline effect for calcium magnesium aluminosilicate glasses

In this paper, we discussed the fiber spinnability and mixed alkaline earth effect in the aluminosilicate glasses with MgO replaced by CaO. The high-temperature viscosity, dilatometric and DSC tests were applied. Results show that Kfib shows the opposite results to that from the graphical map of (m:D), while the ΔT only picks one glass sample for fiberizing. The mixed alkaline earth effect manifests itself as minima in viscosity, and characteristic temperatures, but maxima in fragility, thermal expansion, which are related to the increased entropy, the loose network, and weak bonds, not the network connectivity. The lower values for Mg end-member would be attributed to the higher field strength that would attract the nearest oxygen and cause more disturbance to the glass structure. The free volume is not related to the mixed effects in the viscosity and characteristic temperatures but should have a relationship with the melt strength index.