E-glass fiber is the most widely used glass fiber for reinforced composite materials of aircrafts, automobiles and leisure equipments. But recently researches are being progressed to reduce boric oxide from 8 % to 0 (zero), as is called ‘Boron free E-glass’, because of increasing material cost, environmental problem, and improving chemical resistance and mechanical properties of E-glass fiber. In this study, we fabricated the bulk glass and fiber glass of ‘Boron free E-glass (BF) compositions’, and characterized thermal properties and optical properties. ‘Boron free E-glass (BF)’ was obtained by the melting of mixed batch materials at 1550oC for 2 hrs with different Al2O3 compositions 5~10 %. We obtained transparent clear glass with high visible light transmittance value of 81~86 %, and low thermal expansion coefficient of 4.2~4.9 × 10−6/oC and softening point of 907~928oC. For the chemical resistance test of ‘BF’ fiber samples, we identified that the higher alumina contents gives the better corrosion resistance of glass fiber.