Monday, August 20, 2018

Tampering Glass

Silicon dioxide  \(Z=14+8*2\), \(SiO_2\) density \(2.196\,\,gcm^{-3}\) and molar mass \(60.08\,\,g\,mol^{-1}\)

\(v_{boom}=3.4354*\cfrac{2.196*10^{3}}{14+8*2}=251.47\,ms^{-1}\)

\(T_{boom}=251.47^2*\cfrac{60.08*10^{-3}}{3*8.3144}=152.32\,K\)  or  \(-120.83\,^{o}C\)

\(T_{p}=251.47^2*\cfrac{60.08*10^{-3}}{2*8.3144}=228.48\,K\)  or  \(-44.67\,^{o}C\)

neither of which is tempering temperature of about \(620\,^{o}C\).

We don't have a speculative relation between \(T_{boom}\) and glass tempering.

If we focus on only the silicon atoms in the structure and adjust both density and molar mass accordingly,

adjusted density,  \(\rho_{adj}=2.196*\cfrac{28.1}{28.1+16*2}=1.027\,gcm^{-3}\)

adjusted molar mass,  \(M_{adj}=60.08*\cfrac{28.1}{28.1+16*2}=28.09\,g\,mol^{-1}\)

So,

\(v_{boom}=3.4354*\cfrac{1.027*10^{3}}{14}=252.01\,ms^{-1}\)

\(T_{boom}=252.01^2*\cfrac{28.09*10^{-3}}{3*8.3144}=71.52\,K\)  or  \(-201.63\,^{o}C\)

there is a slight increase in the value of \(v_{boom}\) but \(T_{boom}\) is of a lower value than previously.

The other significant ingredient in glass is Sodium oxide \(Z=12*2+8\), \(Na_2O\) of density \(2.27\,\,gcm^{-3}\) and molar mass \(61.98\,\,gcm^{-3}\).  Both physical properties of which are similar to silicon dioxide.

\(v_{boom}=3.4354*\cfrac{2.27*10^{3}}{12*2+8}=243.70\,ms^{-1}\)

\(T_{boom}=243.70^2*\cfrac{61.98*10^{-3}}{3*8.3144}=147.57\,K\)  or  \(-125.58\,^{o}C\)

which is too low.

Maybe it is Calcium oxide \(Z=20+8\), \(CaO\) of density \(3.34\,\,gcm^{-3}\) and molar mass \(56.08\,\,gcm^{-3}\) that plays a role in tempering glass,

\(v_{boom}=3.4354*\cfrac{3.34*10^{3}}{20+8}=409.79\,ms^{-1}\)

\(T_{boom}=409.79^2*\cfrac{56.08*10^{-3}}{3*8.3144}=377.55\,K\)  or  \(104.4\,^{o}C\)

\(T_{p}=409.79^2*\cfrac{56.08*10^{-3}}{2*8.3144}=566.33\,K\)  or  \(293.18\,^{o}C\)

but lime together with aluminium oxide \(Al_2O_3\), and magnesium oxide \(MgO\), are added to counter sodium carbonate \(Na_2CO_3\) that makes glass water soluble.  The three additives are to provide for a better chemical durability in glass.

For completeness sake,

Aluminium oxide \(Z=13*2+8*3\), \(Al_2O_3\) of density \(3.987\,\,gcm^{-3}\) and molar mass \(101.96\,\,gcm^{-3}\)

\(v_{boom}=3.4354*\cfrac{3.987*10^{3}}{13*2+8*3}=273.94\,ms^{-1}\)

\(T_{boom}=273.94^2*\cfrac{101.96*10^{-3}}{3*8.3144}=306.75\,K\)  or  \(33.6\,^{o}C\)

\(T_{p}=273.94^2*\cfrac{101.96*10^{-3}}{2*8.3144}=460.13\,K\)  or  \(186.98\,^{o}C\)

...and Magnesium oxide \(Z=12+8\), \(MgO\) of density \(3.6\,\,gcm^{-3}\) and molar mass \(40.304\,\,gcm^{-3}\)

\(v_{boom}=3.4354*\cfrac{3.6*10^{3}}{12+8}=618.37\,ms^{-1}\)

\(T_{boom}=618.37^2*\cfrac{40.304*10^{-3}}{3*8.3144}=617.86\,K\)  or  \(344.71\,^{o}C\)

\(T_{p}=618.37^2*\cfrac{40.304*10^{-3}}{2*8.3144}=926.80\,K\)  or  \(653.65\,^{o}C\)

Try tempering glass at temperatures given by \(T_{p}\) values for Aluminium oxide (\(186.98\,^{o}C\)) and Magnesium oxide (\(653.65\,^{o}C\)).

Good luck.