Thermal Conductivity of a Glass: I. Measurement by the Glass–Metal Contact

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In this Subject: <a title="Chemical Engineering" href="/content/subcat?j_subject=165&j_availability=">Chemical Engineering
By this author: van der Tempel L. ;&nbsp; Melis G.P. ;&nbsp; Brandsma T.C.

Authors: van der Tempel L.; Melis G.P.; Brandsma T.C.

Source: Glass Physics and Chemistry, Volume 26, Number 6, 12 November 2000 , pp. 606-611(6)

Publisher: MAIK Nauka/Interperiodica

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Abstract:

The thermal (phonon) conductivity of glass has been measured by contacting the sample with a metal at a different uniform initial temperature. The subsequent temperature response in the metal is measured by a tiny thermocouple just underneath the (contact) surface. The coefficient of heat penetration lgr rgr c_p follows directly from the fitted asymptotic temperature jump or drop for long times. Division by the separately measured heat capacity rgr c_p yields the thermal conductivity lgr . The conductivity measurement reproducibility was sgr = 3%. The standard deviation between validation measurements and round robin test results on Pyrex glass was sgr = 5.8%, somewhat more than the accuracy sgr = 5.2% of the round robin test results. The measurement method is insensible for slight imperfections of the thermal contact and infrared radiation diffusion (photon conductivity) in a hot glass. The method has been used with minor modifications for solid and molten samples at temperatures of 50–850°C and conductivities of 0.1–25 W/(m K). The thermal (phonon) conductivity of the investigated soda-lime silicate glasses increases slightly ( sim 27–30%) with temperature from ambient up to around the glass transition.