A comprehensive study of the batch-to-melt (BtM) conversion process was carried out on a single high-boron alkaline earth aluminosilicate glass composition, which is relevant to manufacturing high-performance fiberglass for highend electronic applications. In the study, we used several techniques to trace the BtM process from room temperature up to 1400 • C, namely isotherm batch heat-treatment, X-ray diffraction (XRD), hot-stage microscopy (HSM), hightemperature differential scanning calorimetry (DSC), and Fourier transform infrared (FT-IR). In the BtM process, the intermediate aluminum borate phase (Al 4 B 2 O 9 ) between 1000 and 1100 • C was identified. The formation of Al 4 B 2 O 9 is explained in conjunction with the dihydroxylation of kaolin. For the first time, the potential use of the FT-IR method in studying the BtM process was demonstrated, including the dissolution of sand above 1100 • C.