Physical, structural and optical characterization of silica-borotellurite glasses containing vanadium and nickel ions by Mohd Nor, Nurhayati, Mohamed Kamari, Halimah, Abdul Latif, Amirah, Mohd Shah, Nurisya, Shahrol Nidzam, Nazirul Nazrin, Yusof, Nur Nabihah, Boukhris, Imed, Kebaili, Imen