Topic: Do I not understand? Lead in glass a barrier to fluorescence of uranium opaline?

[flying free]

I've just been reading on something else and this caught my eye.  Am I translating this incorrectly? or misunderstanding what's written?
And does it just pertain to uranium opaline glass?

Pressglas-korrespondenz 2005-2

https://pressglas-korrespondenz.de/aktuelles/pdf/pk-2005-2w-mannoni-opalines.pdf

 Seite 132 von 276

Quote:

'In Berlin, wo Jean Kunckel als großer Alchimist gewesen war, isolierte und bestimmte hundert Jahre später
1789 ein Professor der Chemie Klaproth (1743 - 1817)
das Uran. Von Uran, als oxydierend, gibt es grüne Uranoxyde, die nicht fluoreszieren. Mehr oxydiert, gibt es
zusammengesetzte gelbe Uranoxyde mit einer grünen
Fluoreszenz. Wenn man der Zusammensetzung der
Glasmasse Natrium-Uranate hinzufügt, erhält man ein
Glas mit zitronen-gelber Färbung durch Brechung, klar
grün, leicht opalisierend durch Reflektion. Diese Dichroïsmus genannte Eigenschaft entsteht durch Fluoreszenz, die das Uran im Glas hervorruft. Blei ist ein Hindernis für die Fluoreszenz. So hat man kein Interesse,
Kristall mit diesem merkwürdigen Oxyd zu opalisieren.
Nur Glas wird also mit Uran gefärbt werden.'

Using google translate I think that reads (my bold):

'In Berlin, where Jean Kunckel had been as a great alchemist, isolated and determined a hundred years later
1789 a professor of chemistry Klaproth (1743 - 1817)
the uranium. Of uranium, being oxidizing, there are green uranium oxides that do not fluoresce. More oxidized, there is
composite yellow uranium oxides with a green one
Fluorescence. If you look at the composition of the
Adding sodium uranate to glass mass gives a
Glass tinted lemon-yellow by refraction, clear
green, slightly opalescent due to reflection. This property, called dichroism, is caused by fluorescence caused by the uranium in the glass. Lead is an obstacle to fluorescence. So you have no interest
To opalize crystal with that strange oxide.
So only glass will be colored with uranium.'

(Still wondering where the Queen Victoria bowl was made obviously and trying to work out whether it was lead glass)

[Ekimp]

If you get rid of the ‘returns’ at the end of the lines before translation, then the translation makes more sense:

“In Berlin, where Jean Kunckel had been a great alchemist, and a hundred years later in 1789, a professor of chemistry Klaproth (1743 - 1817) isolated the uranium.

Of uranium, as oxidising, there are green uranium oxides that do not fluoresce. More oxidised, there are compound yellow uranium oxides with a green fluorescence. If you add sodium uranium to the composition of the glass mass, you get a glass with lemon-yellow colouring by refraction, clear green, slightly opalising by reflection. This property called Dichroïsmus is created by fluorescence, which the uranium causes in the glass. Lead is an obstacle to fluorescence. So you have no interest in opalising crystal with this strange oxide. So only glass will be coloured with uranium.”

[flying free]

Thanks for trying to help Ekimp. What I meant was whether I was reading it correctly i.e. I read it that opaline uranium glass was not found in lead glass items.  That it needed non-lead glass. Either translation is similar and I wondered whether I'd understood that point correctly.

[Anne]

My reading of it would be that lead in crystal prevents the uranium from creating the familiar uranium glow we see in non-lead glass. This would make sense as lead was (still is?) used to line containers in which uranium could be stored to prevent radiation contamination, so perhaps the lead in the crystal somehow prevents the uranium from doing its stuff?

It might be worth using the Ask a Question service at CMOG / Rakow Library as they have someone who seems able to answer this type of question, see here https://libanswers.cmog.org/faq/143932

[flying free]

I will Anne and thanks so much for the link

I suppose  my basic query is whether that uranium glass QV bowl could have been produced in Britain or was it  produced by a Bohemian maker not using lead in their batch. i.e. did all the big makers here use lead in their batch in the 1830s?

Or - like John Ford, were they using uranium in lead glass batches anyway?  to create a colour, as they wouldn't have known about the fluorescence really then.
https://www.glassmessages.com/index.php/topic,70066.msg403520.html#msg403520

[chopin-liszt]

The fluoresence arises from the radioactive component of the metal.
There are three isotopes of uranium, U-234, U-235 and U-238. Only the latter two are radioactive, and neither is terribly strong, they are just alpha emitters. A weak source, easily stopped with a sheet of paper. Only harmful if ingested.
(This is a very simplistic explanation. Other isotopes can be created and we are not talking about depleted uranium which is the really dangerous stuff.)

You might be aware that lead lined boxes are what radioactive stuff is kept in? Lead stops even stronger activity than Uranium.
I imagine lead in the glass might have the same shielding effect.

Anne and me cross-posting. 

[flying free]

Thank you both

So if it turns out to be correct that lead stops uranium fluorescing then for the sake of debate I might reasonably assume that the V&A QV bowl was probably made with unleaded glass.  Which means if it was made here it in 1837 it would have been made by a maker using non lead crystal in the batch.  I wonder did they routinely make up both a leaded crystal for clear cut glass and a non leaded batch for particular reasons to do with colour?

Or did they just add uranium to the lead batches, to create a colour. They wouldn't have known about the fluorescence at that time would they?
See John Ford recipe here:
https://www.glassmessages.com/index.php/topic,70066.msg403520.html#msg403520

[chopin-liszt]

The weakly radioactive alpha particles have enough energy to shift the wavelength of light you are using,(uv) into the wavelength of the glow (green) you see.
That is what radioactive fluoresence is.
Fluoresence is not a property of uranium, per se.
The lead will block the particles from progressing, but they do not stop what the uranium is doing itself.
(I'm being pedantic about you saying the lead stops it from fluorescing, m, 'cos it doesn't, not really.)
Fluoresence is the shifting of the light from one (dullish) wavelength to the brighter one.
It sort of happens inbetween the item, the light source and your eyes.

There are other non-radioactive chemicals which are fluorescent. eg fluorescene.

[flying free]

ok, I vaguely follow that Sue   Thanks for taking the time to explain.

I think the article in Pressglas-korrespondenz was trying to make a point though about using uranium oxide in lead glass.
Was it perhaps about making an opalescent or opaline effect with uranium and that in lead glass the lead stopped that effect happening maybe?   The article appears to indicate that there was no interest in using uranium oxide in lead crystal batches but did it mean only in the instance of opaline/opalescent effect.  Could it be that the opalescent or opaline effect didn't happen in lead glass thereby indicating that opalescent uranium glass or opaline uranium glass is only found in Bohemian non lead glass.

It's trying to make a point but I don't know which point   I suppose it could be the explanation as to why there may be no opaline/opalescent uranium glass French opalines (lead glass) but only Bohemian ones (non-lead glass)?  I don't know if that's true btw but I don't recall seeing any (not that my list of viewing is exhaustive at all though).

John Ford seemed apparently happy with his uranium oxide in lead glass outcome. 

[glassobsessed]

Lead was added to give the resulting glass good clarity, surely counter productive if you want an opaline. A byproduct of adding lead is that it makes the glass softer so it is easier to cut, not certain about this but it may make it less brittle too.

John