Effects of mixed alkaline earth oxides additive on crystallization and structural changes in borosilicate glasses

The effects of mixed alkaline earth oxides on crystallization and structural changes in a multi-component borosilicate glass system are studied by using X-ray diffraction (XRD) and transmission electron microscope (TEM). It is found that the crystallization is decreased with increasing alkaline earth oxide content and there are also a series changes occurred in TEM images. This paper introduces the conception that alkaline earth ions tend to occupy their preferred sites regardless of glass systems. This conception is assisted to explain the TEM images to some extent by suggesting a simple structural model about non-bridging oxygen in glass network. The conception also indicates a ‘blocking effect’ existing in such a multi-component borosilicate glass system, which may be responsible for XRD results in chief. In addition, the structural model suggested by TEM results refers a new unit of Si–O–M2+–O–B, which helps in understanding the minimum exhibits in XRD results. Moreover, a dielectric test is taken to study glass properties in detail.