Abstract: The borosilicate glass has excellent thermal shock resistance and excellent optical performance. This paper was mainly studied on influence of Al2 O3 on the structure and properties of the borosilicate glass. The structure of borosilicate glass was analyzed by infrared spectra at different contents of Al2 O3 . The thermal expansion coefficient, transition temperature, softening temperature, viscosity and chemical stability of the glass were tested. The result show that: with the addition of Al2 O3 , the [ BO4 ] in the glass structure decreased, and the [ BO3 ] increased correspondingly, so glass structure becomes more loose;The thermal expansion coefficient of glass is increased, and the Tg and the expansion softening point Td decrease, the chemical stability is reduced; However, the softening point Tf of the glass decreases with the increase of the Al2 O3 content when the Al2 O3 content is less than 3%, and it is opposite when the Al2 O3 content is more than 3%. the high temperature viscosity of the glass increases with the addition of Al2 O3 , but the low temperature viscosity decreases.

Key words: borosilicate glass;infrared spectrum;thermal expansion;viscosity;chemical stability