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  1. #31

    Default Re: Wavelengths of light, and respective degredation...

    Knowledge, wisdom, and understanding
    Just trying to figure out if different colors of glass/opaque could stop certain essential oils from smelling nasty. Like Grapefruit into sulphur compunds.
    Pedantic has a negative connotation? sh!iiiieet.
    Currently wearing: Royal Mayfair by Creed

  2. #32
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    Redneck Perfumisto's Avatar
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    Default Re: Wavelengths of light, and respective degredation...

    Quote Originally Posted by Astaroth View Post
    I can provide one data point here. I have a 125ml bottle of Polo Sport that apparently rolled under the seat of my car at some point last summer. It got stuck under there for almost a week, getting pushed up to 100 degF pretty frequently since my car was being parked in one of the hottest parts of the San Fernando Valley.

    I am still using the bottle today, and the week of baking it experienced last summer does not seem to have impacted the fragrance at all. It still has all its longevity too. I was all set to toss it out and buy a new bottle, but I didn't need to.
    Very interesting! It does seem that well-sealed bottles do nicely against that level of heat for many frags. I think it's poorly sealed bottles that get baked hard in the trunks of black cars and the like which tend to suffer noticeably. Your experience is consistent with Luca Turin's 90:10 light/heat frag danger estimate.

    Quote Originally Posted by Snafoo View Post
    Because we're pedantophiles, of course!
    LMPAO! And, of course, because we're not evil! (Well, at least not always...)

    Quote Originally Posted by Astaroth View Post
    I'll participate in any thread involving degradation, respective or not.
    You mean we're not talking about bad Milla Jovovich movies, political extremists, and sexual B&D? Crap! I'm on the wrong thread!

    Quote Originally Posted by Asha View Post
    Pedantic? I thought we were having a light discussion...

    LOL
    Good Lord. As long as it took me to get that, I think the free radicals must have destroyed my brain. Time for more red wine antioxidants.

    Quote Originally Posted by Asha View Post
    KBE, I am not sure about the author you refer to--perhaps he is a dedicated and serious scientist. Or, maybe he is an imaginative sort, but I think that is very enjoyable also. Pop-science or serious-science aside, I sure do miss the days when I could watch Star Trek and accept most of the tech-babble....
    Yes, but those were the days that made us fall in love with science. It took me the rest of my life to realize that art is just as important, if not more so, and not to be so hard on the babble. Hard science boxes under the curvature of the universe and includes too little. Soft science and art box around it and include too much. We all seek to describe the same beauty.

    Quote Originally Posted by surreality View Post
    Overall though moon_fish's answer is a good summation. Each compound will react to light differently due to things like type of molecule, the types of bonds, the bond angle, and other intra and intermolecular factors will cause each compound to react in a certain manner so there is no one answer to your question.
    ...so there is no one answer to your question.

    The discussion begins as one point, expands in many beautiful ways, and returns to a single point of truth. Every fragrance is its own story. Even when it dies.

    Now, where was I? Oh, yes. Bought Armani Code today. In the opaque black bottle!
    Last edited by Redneck Perfumisto; 24th July 2008 at 04:45 AM. Reason: ...because words don't come with their own spell-checkers.

  3. #33

    Default Re: Wavelengths of light, and respective degredation...

    Would the smell of a fragrance change if left in the hot summer sun for a few days,

  4. #34

    Default Re: Wavelengths of light, and respective degredation...

    Quote Originally Posted by Redneck Perfumisto View Post
    1) Skunky beer comes from small amounts of sulfur-containing compounds which are formed due to light exposure.

    2) It happens due to visible light, not UV.

    3) It happens with clear or even green glass, but is diminished by amber glass.

    4) The basic mechanism is that a substance other than the fragrance chemicals themselves absorbs the light, and that substance is the bad actor that starts everything. The fragrance chemicals are never themselves electronically excited by the light, which in their case would have to be UV. In the case of beer, the bad actor is riboflavin.

    5) The substance that does absorb the (visible) light then steals an electron from the fragrance chemicals, and that starts a path which not only eats up the fragrance chemical, but also creates a new, stinky one.

    6) The implications for frags are: (a) glass can mostly stop UV, but your frags are still at risk for sunlight damage by visible light, unless they are in dark or opaque glass (as Astaroth said). (b) although UV normally does more damage per photon, it is the specific frequency activating whatever bad stuff is actually possible that is the most dangerous, and (c) whatever happens depends markedly on the total mix of substances which are present in the juice, and what bad things are possible given that mix.

    Now, still, I do like Irish's suggestion about actually demonstrating what can happen (even if he was only trying to scam us out of our good stuff! ), so I'd like to do some kind of home experimentation, sorta like a Great Internet Perfume Skank-Off. We can get pictures and scent reports on pairs (or greater) of vials, one a control, and the other(s) subjected to various skank-inducing conditions. Not exactly hardcore science, but we can't exactly afford to buy a GC-MS on Grant's spare server change. Still we can do some simple bathroom science that's kinda fun, and will definitely give us a feeling for the magnitude of this thing.

    So what I'm saying is that we should stop simply whining about those frags we don't like, and actually get a bit medieval on 'em! Whaddaya say, people? <evil scientist laughter>Bwah-ha-ha-ha-ha!</evil scientist laughter>. Who's with me? <signature revoked below/>
    Great research, Redneck!
    I always believe that in perfume spoiling should be some other agents not only perfume molecules.
    So - dyes also includes some kind of degradation, that`s for sure.
    And it makes sense that modern perfumes has less golden-brown colours than all the vintage juices were.

    I`d suggest that chemistry chefs in perfume labs do know the weakest link in the chain. But never tells you what it is in particular perfume made in their lab.

    Also it`s doubtful that aromachemicals has mainly UV-spectrum of absorption - just the fact they are translucent does not prove it. It could be also invisible infrared spectrum (rotational spectrums are IR spectrums - when photons brings energy enough to rotate the molecule. It`s the easiest way to move molecule, next is oscillatory movement).

    UV spectrum of absorption gives us another mechanism of absorption, when photon energy is big enough to separate the weakest electron from molecule. And that`s about free radicals and it`s the worst way to spoil perfume (except dirty fingers in perfume bottle or dilution with whatever you find out on kitchen).


    `I suppose this is why perfumes with more naturals go bad relatively easily--they have more impurities which degrade the scent when they recombine to form new molecules`.
    Asha,
    I believe that those `impurities` are the best part of naturals, and they gives natural oils the most sought after quality. So let`s put it like - They have more beautiful chemical components comparing to synthetics, and therefore they have more chances to be spoiled by light and spoil all the perfume.

    Also,
    it`s great to find out so many colleagues!!!
    Vetiver The Great!!!

  5. #35

    Default Re: Wavelengths of light, and respective degredation...

    Quote Originally Posted by Redneck Perfumisto View Post
    1) Skunky beer comes from small amounts of sulfur-containing compounds which are formed due to light exposure.

    2) It happens due to visible light, not UV.

    3) It happens with clear or even green glass, but is diminished by amber glass.

    4) The basic mechanism is that a substance other than the fragrance chemicals themselves absorbs the light, and that substance is the bad actor that starts everything. The fragrance chemicals are never themselves electronically excited by the light, which in their case would have to be UV. In the case of beer, the bad actor is riboflavin.

    5) The substance that does absorb the (visible) light then steals an electron from the fragrance chemicals, and that starts a path which not only eats up the fragrance chemical, but also creates a new, stinky one.

    6) The implications for frags are: (a) glass can mostly stop UV, but your frags are still at risk for sunlight damage by visible light, unless they are in dark or opaque glass (as Astaroth said). (b) although UV normally does more damage per photon, it is the specific frequency activating whatever bad stuff is actually possible that is the most dangerous, and (c) whatever happens depends markedly on the total mix of substances which are present in the juice, and what bad things are possible given that mix.

    Now, still, I do like Irish's suggestion about actually demonstrating what can happen (even if he was only trying to scam us out of our good stuff! ), so I'd like to do some kind of home experimentation, sorta like a Great Internet Perfume Skank-Off. We can get pictures and scent reports on pairs (or greater) of vials, one a control, and the other(s) subjected to various skank-inducing conditions. Not exactly hardcore science, but we can't exactly afford to buy a GC-MS on Grant's spare server change. Still we can do some simple bathroom science that's kinda fun, and will definitely give us a feeling for the magnitude of this thing.

    So what I'm saying is that we should stop simply whining about those frags we don't like, and actually get a bit medieval on 'em! Whaddaya say, people? <evil scientist laughter>Bwah-ha-ha-ha-ha!</evil scientist laughter>. Who's with me? <signature revoked below/>
    Great research, Redneck!
    I always believe that in perfume spoiling should be some other agents not only perfume molecules.
    So - dyes also includes some kind of degradation, that`s for sure.
    And it makes sense that modern perfumes has less golden-brown colours than all the vintage juices were.

    I`d suggest that chemistry chefs in perfume labs do know the weakest link in the chain. But never tells you what it is in particular perfume made in their lab.

    Also it`s doubtful that aromachemicals has mainly UV-spectrum of absorption - just the fact they are translucent does not prove it. It could be also invisible infrared spectrum (rotational spectrums are IR spectrums - when photons brings energy enough to rotate the molecule. It`s the easiest way to move molecule, next is oscillatory movement).

    UV spectrum of absorption gives us another mechanism of absorption, when photon energy is big enough to separate the weakest electron from molecule. And that`s about free radicals and it`s the worst way to spoil perfume (except dirty fingers in perfume bottle or dilution with whatever you find out on kitchen).


    `I suppose this is why perfumes with more naturals go bad relatively easily--they have more impurities which degrade the scent when they recombine to form new molecules`.
    Asha,
    I believe that those `impurities` are the best part of naturals, and they gives natural oils the most sought after quality. So let`s put it like - They have more beautiful chemical components comparing to synthetics, and therefore they have more chances to be spoiled by light and spoil all the perfume.

    Also,
    it`s great to find out so many colleagues!!!
    Vetiver The Great!!!

  6. #36
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    Default Re: Wavelengths of light, and respective degredation...

    Quote Originally Posted by moon_fish View Post
    Also it`s doubtful that aromachemicals has mainly UV-spectrum of absorption - just the fact they are translucent does not prove it. It could be also invisible infrared spectrum (rotational spectrums are IR spectrums - when photons brings energy enough to rotate the molecule. It`s the easiest way to move molecule, next is oscillatory movement).
    You're right about IR - both UV and IR are always strong for organics. The fact that these can be used to fingerprint a substance pretty much depend on it. It's just that you have to get pretty short in the UV to get to where things like alkanes start absorbing, and when you get out there, it's like Snafoo was saying - all kinds of bad things start happening. Any UV that gets through your glass is going to cause trouble. There's almost no way around that. I have some CK Crave in a plastic bottle, and am very curious if it's at risk for UV, or if the plastic was treated to prevent UV transmission. The fragrance smells bad to most people anyway, so not sure if that's much of a test!

    Quote Originally Posted by moon_fish View Post
    ... and it`s the worst way to spoil perfume (except dirty fingers in perfume bottle or dilution with whatever you find out on kitchen).
    LOL - that's right! Nothing like human oils or isopropyl alcohol to ruin a perfume!

    Quote Originally Posted by moon_fish View Post
    Also,
    it`s great to find out so many colleagues!!!
    Absolutely! Although the best science thread ever on this board had to be the Schroedinger's Frag thread, a.k.a., Should I open the box?
    * * * *

  7. #37

    Default Re: Wavelengths of light, and respective degredation...

    Quote Originally Posted by moon_fish View Post
    I believe that those `impurities` are the best part of naturals, and they gives natural oils the most sought after quality. So let`s put it like - They have more beautiful chemical components comparing to synthetics, and therefore they have more chances to be spoiled by light and spoil all the perfume.
    Some of the impurities found in natural fragrances add nothing to the scent; things like the waxes, fatty acids and their esters are carried into the essential oil in the extraction process. These compounds can go rancid quite quickly. But you are right in that a natural essential oil will be more complex and more pleasing to the nose of most people than a synthetic approximation of the same oil.

  8. #38

    Default Re: Wavelengths of light, and respective degredation...

    YSL Pour Homme is the only fragrance that I've ever experienced a rancid bottle of. The bottle is clear, perhaps it was light degradation.

  9. #39
    Asha's Avatar
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    Default Re: Wavelengths of light, and respective degredation...

    Quote Originally Posted by Redneck Perfumisto View Post
    I have some CK Crave in a plastic bottle, and am very curious if it's at risk for UV, or if the plastic was treated to prevent UV transmission. The fragrance smells bad to most people anyway, so not sure if that's much of a test!
    I think most non-reactive plastic containers are polypropylene or polyethylene. Polyester, polycarbonate, acrylic are all great, but I don't see many non-reactive (ie, FDA approved) containers for cosmetics in these materials.

    At any rate, plastic is typically coated if it is to filter UV--the ones I have seen (usually acrylic sheeting or tubing used to filter UV from artwork). This coating has a yellowish cast to it, and chances are it is not non-reactive when in contact with liquids and gels. I am sure it is also very expensive.

    When I go to work tomorrow, and if I remember, I'll see if my optical materials catalog has transmission data for plastics. Of course, no plastic atomizers will be made from optical grade plastics (way too expensive), but it is worth it to see how far down they actually go to the UV.

    Most glasses that pass visible light will also pass light from the near infrared, up to around 2 micron wavelength.

    Anyway, I'll see what I can come up with!

  10. #40
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    Default Re: Wavelengths of light, and respective degredation...

    Ok, I checked data for plastic, and it is not very complete. As a baseline, a typical borosilicate glass (BK7 from Schott) will transmit 99% from 1530 nm to 365 nm. It falls off rapidly in the UV region, and more slowly in the IR region.

    The plastic data I have is far less extensive, and the catalog says that acrylic and polycarbonate are designed for the range 1014 to 365 nm. It does not show me how rapidly the transmission falls off at the two ends.

    365 nm is indeed UV, but is considered "near UV". So, this region consists of SOME damaging UV, but other parts of the UV spectrum are blocked significantly, at least with the glass. Data on the plastic is inconclusive.

  11. #41
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    Default Re: Wavelengths of light, and respective degredation...

    Thanks, Asha. Here is some more info for you. I checked my bottle of Crave - it has 3 separate layers. The outer clam-shell container is type 5 (PP). The bottle that you hold in your hand is type 7 (other). The inner bottle holding the juice itself is not labeled at all, but appears to match the type 7 plastic around it.

    I decided to dig through some of my books, and I found a few interesting paragraphs.

    Here is a quote from one of my books, The Chemistry of Fragrances, referring to an exemplary formulation:

    "The formulation also contains an ultraviolet (UV) radiation absorber, benzophenone-2 [0.50% w/w in final fragrance containing 78% alcohol and 12% fragrance; author note: Uvinul D50 ex BASF AG], to prevent degradation of the fragrance and any dyes by light. Although consumers are encouraged to keep fine fragrances in the dark, the manufacturer needs to protect the product from those customers who insist on storing it on a sunny windowsill!" (exclamation is original)

    There is more in the way of general statements later:

    "Light stability, even though a UV absorber is being used, must also be checked to ensure that the fragrance does not darken unacceptably or that any dyes added do not fade. It may be that, in this case, a different UV absorber works better or that the perfumer needs to change one or two of the ingredients in the fragrance."

    There is also a nice description of a hypothetical perfume heat/light stability test - probably representative of reality. I will post that in another post shortly, to keep the length of this post down (and to get a little shut-eye, as well!)
    * * * *

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