Annealing of this material is accomplished in lehrs. An industrial method to produce a type of this material lays liquid raw materials over tin to form a float. Diffusion of interfering ions described by the Nikolsky–Eisenman equation across this material is seen in electrodes, which can be used to measure pH. Sintering particles of this material into hollow disks creates fritted examples of these materials that are used as filters. Addition of boron trioxide lowers the coefficient of (-5[1])thermal expansion of these materials. (10[2]-5[1])Silica, (10[1])soda ash, and (-5[1])limestone produce the molten form of this material, which is then solidified by blowing. (10[2]-5[1])For 10 points, (10[2])what amorphous material is often used to make lab materials and window panes? ■END■ (10[3])