Will a one-week visit to Thailand affect my single-entry non-immigrant visa?

It will impact your visa in that you will have to use your visa to enter Thailand. You can politely ask the immigration officer if you can not use your visa, but there have been multiple reports of people with visas (even e-visas that are not in the passport) being forced to use their visa when entering Thailand. They don't hand their printed visa to the immigration officer at passport control, but the immigration officer sees it in the computer and requires the person to use it.

So you should expect you will be using your visa when you enter Thailand. Single entry non-immigrant visas give you permission to stay in Thailand for 90 days. This means you will receive a 90 day entry stamp when you enter. Generally when someone has a non-O visa they will be planning to apply for a 1-year extension. For this extension you will need to have your money in the bank for 2 months at the time you apply. That means if you are using banked money, during your 1-week visit, get your Thai bank account open and your money transferred to Thailand.

When you leave, get a re-entry permit at the airport. This will keep your entry stamp alive, meaning it's not immediately invalid as soon as you leave the country. Then when you return you can enter on the same entry stamp in your passport, and you can go to immigration and apply for your 1-year extension once your money has been in your bank account for 2 months.

You could also let your stamp become invalid when you leave and just apply for a new visa when you return home.