'voluntarily work' is correct and usable in written English.
You can use this phrase when you are talking about work that is done out of a person's own free will. For example, "Tim was so passionate about helping his community that he volunteered to work in the local food bank for free."
She was a day reporter there but would voluntarily work mornings and into the night.
At Pace University in New York, students attend school and voluntarily work up to 20 hours a week during the semester.
The graphic images of the unprovoked attack and subsequent heinous mistreatment of our friends exhibits the extraordinary conditions under which we voluntarily work to bring freedom and democracy to the Iraqi people".
Mr. Edwards borrowed heavily from his stump speech, promising to pass a universal health care plan, start a program to help finance college education, and offer incentive pay to teachers who voluntarily work in high-poverty schools.
Under the provisions of a 19th-century law known as the Anti-Deficiency Act, it is quite literally illegal for federal employees deemed nonessential to voluntarily work during a shutdown.
Rather, the business cycle reflects fluctuations in the rate of technological progress, which are amplified by the rational response of workers, who voluntarily work more when the environment is favorable and less when it's unfavorable.
6) Workers themselves might respond by voluntarily working harder.
"Any excuse to escape," he said, adding that he sometimes did so by voluntarily working.
Christopher Hufnagel, a senior vice president for the company, said it was voluntarily working with Michigan regulators to clean up the mess.
Research by the New Economics Foundation shows that voluntarily working less is positive for our wellbeing, but compulsion, especially in the context of an economy not designed to support part-time work, ruins the benefit.
Here is why I feel invisible: the Workplace Gender Equality Agency has recently released a new target-setting toolkit as a resource for those employers who are (voluntarily) working towards equalising gender representation in the workforce.
