identification - "31WOC" on a boost converter, but what datasheet goes with it?

Long shot, I know...

I have this Boost convert 1-5V in out 5.1-5.2V and I hope to modify it for a different output voltage.

So I'm trying to identify and find the datasheet for the main chip.

I think the chip reads 31WOC, but I can't find a datasheet for that number. Anyone familiar what the type is of the chip?

There is no more datasheet than the following:

IN 1-5V
OUT 5.1-5.2 
Current: Rated 600mA (single lithium input), the maximum 700mA (single lithium input)


€ 1,50

Answer

The 31WOC is probably not the actual part number, rather some type of code described in the datasheet for different variants of the chip.

I think I would forget about what the actual part number is, and just locate the feedback pin and adjust the resistor divider as necessary (assuming it's an adjustable regulator). Most use an internal reference of ~1.2V. Look for the pin with this voltage on, attached to the centre of a resistor divider.
If it's a fixed regulator then it's a little more tricky, you will probably have to experiment with a few resistor values from the feedback pin to ground (start with 1-10k?). You will only be able to raise the output voltage this way.

EDIT - on the picture you have added, it looks like the divider is the two resistors at the top right marked "18C" (15k?) and "473" (47k). Measure these resistors, and also the voltage at the pin they are connected to (top right pin of IC). The output voltage formula should be 1.24V * ((Rtop/Rbottom) + 1) which in your case is 1.24V * ((47k / 15k) + 1) = 5.12V, which is around what you are seeing.
Adjust as desired, but be aware if you are increasing the output, that the chip may not be rated for voltages much above it's current level.