Temperature dependence of Young modulus of sodium borosilicate glasses with the same content of Na2O and B2O3

Change in the sound velocity and the Young modulus in the temperature range from 20 to 400 deg C of quartz and sodium borosilicate glasses along the section with similar content of Na2O and B2O3 is investigated. It is established that at 20 deg C the sound velocity along the section remains practically constant. The Young modulus increases in the interval of 100-78 mol % SiO2 compositions from 71.2 to 76 GPa, for 78-45 mol % SiO2 compositions the Young modulus has the maximum values for sodium borosilicate glasses equalling 78±2 GPa. The Young modulus temperature coefficient (MTC) has the maximum positive value 1.60x10-4 K-1 for quartz glass. MTC decreases when decreasing the SiO2 content in sodium borosilicate glasses, at 81 mol % SiO2 its value equals zero