How much of the solar radiation that hits a transparent glass is actually heating the glass?

Question

You have a transparent (borosilicate) glass window. Sun rays are falling on the glass, which is let's say placed horizontally. Some of the radiation passes through the glass, some is reflected back but some is absorbed and heats up the glass. How much of that total radiation is actually absorbed and makes the glass heat up? I speculate that would be somewhere around 2-3%. Any specialist in optics or heat flow?

Answer 1

The transmittance of good quality glass 1cm thick ranges from 99.6% to 99.9%, so the absorption is less than .4% in the visible spectrum. It increases in the ultraviolet. But if you have glass covering a box, nearly all the light passes through and heats whatever is in the box. The infrared energy radiated is mostly blocked by the glass. That's what heats a greenhouse.

Answer 2

Would need to know the index of refraction of the glass. If it's "perfectly refractive" then it would not heat up at all, as the individual photons would pass right through it. the higher the index the more collisions will take place within the surface of the glass as photons are reedirected and thus more heat is absorbed.

Answer 3

how much is absorbed and not transmitted on the other side?