structure becomes progressively more perceptible. This should be in fact explain the high deformation of the silicate fiber which is produced by means of profound acid treatment through which the substances which fill in the glass framework are removed. Time in min Losses in wt. o 2, Deformation of fiber. 1)Alumino ig. 3. The dependence of the modu borosilicate; 2)silicate. lus of elasticity of fiber on the quanti The chain structure of the silicate framework is also discernible on heating glass fiber. As is known, elastic lag increases considerably in glass fibers as the temperature is raised, especially close to vitrification temperature(Fig. 4). Here the increase in elastic lag occurs simultaneously with the lowering of the viscosity of the glass(Fig. 5). These facts testify to the increase in molecule mobility with the weakening of the cementing effect the oxides which fill the framework. It may be assumed that as the quantity of low-melting constituents in, the glass is increased, or with an increase in the heating temperature, when their viscosity is greatly reduced, the influence of these substances on the silicate framework Is weakened, and its chain structure already becomes noticeably apparent. 20 ep7 Time, hr Flg. 4. The variations in the elastic lag on heating Fig. 5. The elastic lag on varying the vig the fiber cosity of fibers of different compositions. The extensive ramification of the chains and also the cementing effect of the constituents which fill the silicate framework are the main cause of the rigid structure of silicate glasses, and their low deformation.structure becomes progressively more perceptible. This should be in fact explain the high deformation of the silicate fiber which is produced by means of profound acid treatment through which the substances which fill in the glass framework are removed. q00 300, '~ 200 u..... V Z ! ~000 ~ I00 5000 qO00 ".. JOOO e:xo 2000 1000 \ NNN•\ \ 100 200 300 0 10 20 80 Time in min Losses in wt. % ~0 Fig. 2. Deformation of fiber. 1)Alumino- Fig. 3. The dependence of the modu￾borosilieate; 2) silicate, lus of elasticity of fiber on the quanti￾ty of oxides driven off from it. The chain structure of the silicate framework is also discernible on heating glass fiber. As is known, the elastic lag increases considerably in glass fibers as the temperature is raised, especially close to vitrification temperature (Fig. 4). Here the increase in elastic lag occurs simultaneously with the lowering of the viscosity of the glass (Fig. 5). These facts testify to the increase in molecule mobility with the weakening of the cementing effect of the oxides which fill the framework. It may be assumed that as the quantity of low-melting constituents tnthe glass is increased, or with an increase in the heating temperature, when their viscosity is greatly reduced, the influence of these substances on the silicate framework is weakened, and its chain structure already becomes noticeably apparent. r,0 6,17 5,a ' "~ q,o / 3,0 o z,o t.ra I,o _.9.....x -'500' ~00 ~ 3oo~ zoo 01-1 o tao o raa 0 1 2 3 ~ 5 6 0~4 Time, hr 7,0 5 6,0 ~ Z,O 1,0 [,. 9 Fig. 4. The variations in the elastic lag on heating the fiber. Fig. 5 . The elastic lag on varying the vis￾cosity of fibers of different compositions. The extensive ramification of the chains and also the cementing effect of the constituents which fill the silicate framework are the main, cause of the rigid structure of silicate glasses, and their low deformation. 611