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Just to clear up some speculation in regards to Gorilla Glass 3 vs. 2 using science and official specification documentation.

The difference in brittleness (correlated by Young's Modulus) between Gorilla Glass 2 and 3 is 71.5 and 69.3 GPa respectively. This is a 3% difference, and barely any difference. Just as a comparison: glass is usually around 50-90 GPa, mother of pearl is on average 70 GPa. (lower=more elastic, higher=more brittle)

The axial stress (aka Poisson's Ratio) is almost exactly the same, 0.21 to 0.22, which can easily be down to systematic and rounding errors.

The fracture toughness (how hard it is for a crack to elongate/propogate) actually decreased from 0.68 to 0.66 MPa m^0.5, so if you have a crack in your screen, it will spread 3% easier.

And finally, the hardness of the glass did not change. It is just as easy to scratch a Gorilla Glass 2 panel as it is to scratch a Gorilla Glass 3 panel.

tl;dr - There are very little differences between Gorilla Glass 2 and 3. It should not be a deciding factor when you are deciding which phone to buy.
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38 comments
 
Some people seem to be using the excuse that Gorilla Glass 3 is on S4 that means it better than the One with Gorilla Glass 2.
 
From what I saw with the demonstrations at CES it looked like it was much stronger with them dropping ball bearings at twice the height but maybe what they didn't show was that probably both could withstand the increase in height??
Shen Ye
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I believe they compared their glass with competitors. I'm not sure which competitor so I can't pull the specs for them.
 
It's not a tl;dr if you put it at the bottom. 
Shen Ye
 
If you find a screen protector with a high dielectric constant, it will not hinder screen sensitivity and will actually reduce the young's modulus of the glass+protector significantly.
 
Isn't 3 supposed to be significantly thinner than 2 though?
Shen Ye
 
+Jaime Lefebvre Doesn't make a difference. These values take in account of volume. For example, Young's Modulus is in the units of GigaPascals, which is a unit of pressure, and pressure is a measurement dependent on volume.
 
Is there a more significant difference in brittleness between Gorilla Glass 1 and 2?
Shen Ye
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I didn't go find the specification documentation for 1, but I doubt it. Glass is glass, 70 GPa is the ideal region for mobile devices, slightly flexible but will still be hard enough to not get a bunch of scratches.
 
In the comparison at CES, standard sodium glass was used. The demonstration also used a much thicker (5mm) piece of glass than what is actually used on the devices (2mm) we can buy. Manufacturers choose to use thin sheets of glass that can't withstand the same test results. They also create weak points by cutting holes for speakers, buttons etc.

If you want a better, tougher glass than Gorilla Glass, check out Dragontrails glass. 
Shen Ye
 
The dielectric constant of Gorilla Glass isn't that great, making it 5mm thick will severely reduce the sensitivity of the digitiser.
Shen Ye
 
+Neil Lund Looking at the spec sheet for dragontrail, it has a higher Young's modulus at 74, so less flexible and more brittle than GG3. It has a higher shearing modulus so it's tougher, Poisson ratio is within 0.01, but it's most definitely a harder piece of glass, so less prone to scratching, but this is a side effect of a higher Young's modulus. 
 
+Shen Ye Actually, pressure is based on Area, not volume. (but as the test uses a cross-sectional area, the thickness which was the original argument, is taken in to account.)
Shen Ye
 
+Gary LaTraille Ugh yeah you're right, my bad. Funny enough I'm currently revising some materials chemistry....
 
I preffer to have gorilla glass 2 and metal body than gorilla glass3 with plastic back. 
Rich S
 
The plastic back will deform to absorb energy.  A metal body will either dent, or transfer the energy to other components.

It's disingenuous to write off the improvements of GG3 as a rounding error just to push one phone over another.  Anything that improves on scratch and fracture resistance is something most of us care about.
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+Rich Stone  The values it gave were 0.22 and 0.23. It could have easily been 0.2249 to 0.2250. So, yes, it can easily have been a rounding error.

You talk about metal and plastic, but you do realise there are form supports and rubber seals between the glass and the frame right? Hardness didn't increase, it has the same scratch resistance. Fracture resistance actually went down in GG3.

 l2r please.
 
+Shen Ye Do you really think the digitizers sensitivity would be greatly effected by a slightly thicker glass? I think the manufacturers have chosen thinner glass to make their devices thinner, not because the sensitivity of the digitizer is diminished. Just over thinking the it a bit for the heck of it.
Shen Ye
 
Numbers don't lie.
Shen Ye
 
+Neil Lund glass insulated electron flow, but not nearly as much as plastic. The sensitivity to thickness is exponential, doubling the thickness will more than halve the sensitivity.
 
+Shen Ye finally, you saying that there is no practical difference between GG2 and GG3? So I can sue Corning?
Shen Ye
 
Scientifically, it's an amazing feat, but for general use? Not really.
 
i heard its was the same strengh but thinner (the glass) .. 
Rich S
 
You're comparing specific material spec values, but ignoring all test data and corning's own statements on improvements.  Which do you think is more applicable?
Shen Ye
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Biased marketing sentence or actual technical specs?
 
Reminds me of my materials class.
 
Young's Modulus isn't typically a measurement of brittleness, just a relationship between stress and strain. Can you provide some insight into why you're using Young's modulus as the metric? Young's modulus along with strain to failure gets you closer - is there published data on strain allowables for gorilla glass 2 and 3?
 
Do you have a link to the datasheet for GG3?  I'd like to look at the vicker's hardness test result.
 
+Junaid Ahmad What is the quantitative measure of brittleness? It's not strength, but simply a lack of ductility, right? I have a basic understanding of stress-strain relationships, and only recognize brittleness as having a small region of plastic deformation.
 
Great post, thank you for this.
 
is there any extra protection for gorilla glass 1/2/3 with metal case vs plastic?
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