E-Glass fiber (“E” stands for electric) is made of aluminoborosilicate glass with less than 1 wt% alkali oxides. Some
other elements may also be present at low impurity levels. A typical nominal chemical composition of E-glass fibers is
SiO2 54 wt%, Al2O3 14 wt%, CaO + MgO 22 wt%, B2O3 10 wt% and Na2O+K2O less than 2 wt% . Some reported advantages and disadvantages of E-glass fibers are listed in Table 2.