From this equation, the presence of [Cu.sup.2+] in AgCl photochromic glasses
causes the equilibrium in (2) to shift to the left-hand side, while the [Ag.sup.0] formed by UV-vis irradiation is converted back to [Ag.sup.+].
Yet there will be sustainable innovations in building: photochromic glass
for example will soon perhaps be cheap enough to use on a large scale; electrochromic glass is very expensive now, but will presumably become cheaper.
Mr Selbie, who is also the co-chairman of the recently formed Milnsbridge Business Association, said: "Most of our patients come to us from word-of-mouth referrals and we have built up a loyal client base over the years.'' As well as sight and hearing tests, Selbie Opticians now offers the new KodaK digital variofocals range and also new photochromic glasses
which WORK inside so ideal for wearing when driving.