1960's? Whats it got ergoamine tartrate bottles of diethylamine and some Mescaline in it. I want a groovy Chemistry set lemme tell ya.

Hm. Odd.

I figured it had something to do with such weak bonds that the light particles would hit the molecule and break it apart?

But who knows

Not necessarily... this is actually a tough question and I'll just try to explain it for organic molecules.

So we know light is energy and if you break light up it contains different wavelengths, these wavelengths correspond to a different amount of energy. Now, electrons can absorb energy from light pushing them to an excited state. Certain bonds can only absorb a certain amount of energy, or a certain wavelength, the energy it can absorb is quantized... so some molecules will absorb red light (think leaves, thats why they're green, they abosrb red and leave the green for us to see. The leaves are using light for energy, the electrons are getting excited and that energy is being transferred to make chemical bonds to store the energy for later). It a bond absorbs enough light it may have enough energy to break. If you go into certain labs they might have yellow lights, this is because their compound doesn't absorb the energy corresponding to yellow light, but it does for other light.

Thats why chemicals degrade in light. We know that double bonds absorb energy near the visible spectrum, that is why highly conjugated molecules are colored (look at chlorophyll). If you shine enough light, and the right kind of light, onto a conjugated molecule you can break those bonds. This is the reason things bleach in the sun. The sun breaks the conjugated bonds because they absorb its energy, once it breaks those bonds its not absorbing energy (wavelengths/colors) in the visible spectrum. Retinol is also an example of getting energy from light. Certain wavelength excite the chemicals in your eye, those bonds break and signals the enzyme to send a signal.

Hope this helps. I'm assuming the HCl is acting as a catalyst, the protonated species probably absorbs more energy, althought I always thought O- absorbed more.. but I'm not sure on that one.

if and when we choose to consider light to be matter.  When we choose to consider light to be energy,

This is pretty much on point in that light is just energy and nothing more. The part saying that we choose to consider light as matter is no good since matter has mass and light has no mass at all hence it can not be matter. This is the general view of things and it always bugged me because I do not agree with submiting to the view that a photon can have no mass but those that say it does not has studied it far more then me so until I could find proof of mass in a photon I must take there word for it.

It isn't chemistry - light is not a chemical, and has no chemical or physical properties.

However, photons are a special form of matter - and have some form of weird bose-einsteinium mass. IIRC
I might have that term wrong though.